diff --git a/Behavioral/ChainOfResponsibilities/Handler.php b/Behavioral/ChainOfResponsibilities/Handler.php
index 8e6a74d..e6e2f9b 100644
--- a/Behavioral/ChainOfResponsibilities/Handler.php
+++ b/Behavioral/ChainOfResponsibilities/Handler.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\ChainOfResponsibilities;
 
diff --git a/Behavioral/ChainOfResponsibilities/Responsible/HttpInMemoryCacheHandler.php b/Behavioral/ChainOfResponsibilities/Responsible/HttpInMemoryCacheHandler.php
index 2111f25..dcac1e1 100644
--- a/Behavioral/ChainOfResponsibilities/Responsible/HttpInMemoryCacheHandler.php
+++ b/Behavioral/ChainOfResponsibilities/Responsible/HttpInMemoryCacheHandler.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible;
 
diff --git a/Behavioral/ChainOfResponsibilities/Responsible/SlowDatabaseHandler.php b/Behavioral/ChainOfResponsibilities/Responsible/SlowDatabaseHandler.php
index 0273dfd..24ae59b 100644
--- a/Behavioral/ChainOfResponsibilities/Responsible/SlowDatabaseHandler.php
+++ b/Behavioral/ChainOfResponsibilities/Responsible/SlowDatabaseHandler.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible;
 
diff --git a/Behavioral/ChainOfResponsibilities/Tests/ChainTest.php b/Behavioral/ChainOfResponsibilities/Tests/ChainTest.php
index e888d76..bfd189a 100644
--- a/Behavioral/ChainOfResponsibilities/Tests/ChainTest.php
+++ b/Behavioral/ChainOfResponsibilities/Tests/ChainTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Tests;
 
diff --git a/Behavioral/Command/AddMessageDateCommand.php b/Behavioral/Command/AddMessageDateCommand.php
index 91a4f0c..f43e017 100644
--- a/Behavioral/Command/AddMessageDateCommand.php
+++ b/Behavioral/Command/AddMessageDateCommand.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command;
 
diff --git a/Behavioral/Command/Command.php b/Behavioral/Command/Command.php
index 06f3d53..2b9eff8 100644
--- a/Behavioral/Command/Command.php
+++ b/Behavioral/Command/Command.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command;
 
diff --git a/Behavioral/Command/HelloCommand.php b/Behavioral/Command/HelloCommand.php
index a663b4a..5c1f62d 100644
--- a/Behavioral/Command/HelloCommand.php
+++ b/Behavioral/Command/HelloCommand.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command;
 
diff --git a/Behavioral/Command/Invoker.php b/Behavioral/Command/Invoker.php
index a757662..f85509e 100644
--- a/Behavioral/Command/Invoker.php
+++ b/Behavioral/Command/Invoker.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command;
 
diff --git a/Behavioral/Command/Receiver.php b/Behavioral/Command/Receiver.php
index c35bbbc..3241a9b 100644
--- a/Behavioral/Command/Receiver.php
+++ b/Behavioral/Command/Receiver.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command;
 
@@ -17,7 +19,7 @@ class Receiver
     public function write(string $str)
     {
         if ($this->enableDate) {
-            $str .= ' ['.date('Y-m-d').']';
+            $str .= ' [' . date('Y-m-d') . ']';
         }
 
         $this->output[] = $str;
diff --git a/Behavioral/Command/Tests/CommandTest.php b/Behavioral/Command/Tests/CommandTest.php
index 2d0626c..1170f2c 100644
--- a/Behavioral/Command/Tests/CommandTest.php
+++ b/Behavioral/Command/Tests/CommandTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command\Tests;
 
diff --git a/Behavioral/Command/Tests/UndoableCommandTest.php b/Behavioral/Command/Tests/UndoableCommandTest.php
index cbd885c..9573097 100644
--- a/Behavioral/Command/Tests/UndoableCommandTest.php
+++ b/Behavioral/Command/Tests/UndoableCommandTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command\Tests;
 
@@ -23,11 +25,11 @@ class UndoableCommandTest extends TestCase
         $messageDateCommand->execute();
 
         $invoker->run();
-        $this->assertSame("Hello World\nHello World [".date('Y-m-d').']', $receiver->getOutput());
+        $this->assertSame("Hello World\nHello World [" . date('Y-m-d') . ']', $receiver->getOutput());
 
         $messageDateCommand->undo();
 
         $invoker->run();
-        $this->assertSame("Hello World\nHello World [".date('Y-m-d')."]\nHello World", $receiver->getOutput());
+        $this->assertSame("Hello World\nHello World [" . date('Y-m-d') . "]\nHello World", $receiver->getOutput());
     }
 }
diff --git a/Behavioral/Command/UndoableCommand.php b/Behavioral/Command/UndoableCommand.php
index 055ddde..95a3d1a 100644
--- a/Behavioral/Command/UndoableCommand.php
+++ b/Behavioral/Command/UndoableCommand.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Command;
 
diff --git a/Behavioral/Interpreter/AbstractExp.php b/Behavioral/Interpreter/AbstractExp.php
index 5e34736..0fb5dc3 100644
--- a/Behavioral/Interpreter/AbstractExp.php
+++ b/Behavioral/Interpreter/AbstractExp.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Interpreter;
 
diff --git a/Behavioral/Interpreter/AndExp.php b/Behavioral/Interpreter/AndExp.php
index 4218507..10f38d7 100644
--- a/Behavioral/Interpreter/AndExp.php
+++ b/Behavioral/Interpreter/AndExp.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Interpreter;
 
diff --git a/Behavioral/Interpreter/Context.php b/Behavioral/Interpreter/Context.php
index 2a0b2c7..5830848 100644
--- a/Behavioral/Interpreter/Context.php
+++ b/Behavioral/Interpreter/Context.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Interpreter;
 
diff --git a/Behavioral/Interpreter/OrExp.php b/Behavioral/Interpreter/OrExp.php
index 7ff749e..969788c 100644
--- a/Behavioral/Interpreter/OrExp.php
+++ b/Behavioral/Interpreter/OrExp.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Interpreter;
 
diff --git a/Behavioral/Interpreter/Tests/InterpreterTest.php b/Behavioral/Interpreter/Tests/InterpreterTest.php
index 3b1c07a..37dc23d 100644
--- a/Behavioral/Interpreter/Tests/InterpreterTest.php
+++ b/Behavioral/Interpreter/Tests/InterpreterTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Interpreter\Tests;
 
diff --git a/Behavioral/Interpreter/VariableExp.php b/Behavioral/Interpreter/VariableExp.php
index a0f834f..8643d1d 100644
--- a/Behavioral/Interpreter/VariableExp.php
+++ b/Behavioral/Interpreter/VariableExp.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Interpreter;
 
diff --git a/Behavioral/Iterator/Book.php b/Behavioral/Iterator/Book.php
index 34148ad..6059223 100644
--- a/Behavioral/Iterator/Book.php
+++ b/Behavioral/Iterator/Book.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Iterator;
 
@@ -20,6 +22,6 @@ class Book
 
     public function getAuthorAndTitle(): string
     {
-        return $this->getTitle().' by '.$this->getAuthor();
+        return $this->getTitle() . ' by ' . $this->getAuthor();
     }
 }
diff --git a/Behavioral/Iterator/BookList.php b/Behavioral/Iterator/BookList.php
index dd6683e..7726e99 100644
--- a/Behavioral/Iterator/BookList.php
+++ b/Behavioral/Iterator/BookList.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Iterator;
 
diff --git a/Behavioral/Iterator/Tests/IteratorTest.php b/Behavioral/Iterator/Tests/IteratorTest.php
index 3012f46..9dec915 100644
--- a/Behavioral/Iterator/Tests/IteratorTest.php
+++ b/Behavioral/Iterator/Tests/IteratorTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Iterator\Tests;
 
diff --git a/Behavioral/Mediator/Colleague.php b/Behavioral/Mediator/Colleague.php
index 9b2d1a2..030bd45 100644
--- a/Behavioral/Mediator/Colleague.php
+++ b/Behavioral/Mediator/Colleague.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Mediator;
 
diff --git a/Behavioral/Mediator/Mediator.php b/Behavioral/Mediator/Mediator.php
index 3402544..5503df8 100644
--- a/Behavioral/Mediator/Mediator.php
+++ b/Behavioral/Mediator/Mediator.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Mediator;
 
diff --git a/Behavioral/Mediator/Tests/MediatorTest.php b/Behavioral/Mediator/Tests/MediatorTest.php
index 238998f..e6fcdf7 100644
--- a/Behavioral/Mediator/Tests/MediatorTest.php
+++ b/Behavioral/Mediator/Tests/MediatorTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Tests\Mediator\Tests;
 
diff --git a/Behavioral/Mediator/Ui.php b/Behavioral/Mediator/Ui.php
index 2ba2820..d569c9b 100644
--- a/Behavioral/Mediator/Ui.php
+++ b/Behavioral/Mediator/Ui.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Mediator;
 
diff --git a/Behavioral/Mediator/UserRepository.php b/Behavioral/Mediator/UserRepository.php
index 72801fe..bbaf417 100644
--- a/Behavioral/Mediator/UserRepository.php
+++ b/Behavioral/Mediator/UserRepository.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Mediator;
 
diff --git a/Behavioral/Mediator/UserRepositoryUiMediator.php b/Behavioral/Mediator/UserRepositoryUiMediator.php
index e51b3ab..3a8ddf7 100644
--- a/Behavioral/Mediator/UserRepositoryUiMediator.php
+++ b/Behavioral/Mediator/UserRepositoryUiMediator.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Mediator;
 
diff --git a/Behavioral/Memento/Memento.php b/Behavioral/Memento/Memento.php
index 531582f..560d56d 100644
--- a/Behavioral/Memento/Memento.php
+++ b/Behavioral/Memento/Memento.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Memento;
 
diff --git a/Behavioral/Memento/State.php b/Behavioral/Memento/State.php
index a34eeb4..a103b39 100644
--- a/Behavioral/Memento/State.php
+++ b/Behavioral/Memento/State.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Memento;
 
@@ -6,10 +8,10 @@ use InvalidArgumentException;
 
 class State implements \Stringable
 {
-    const STATE_CREATED = 'created';
-    const STATE_OPENED = 'opened';
-    const STATE_ASSIGNED = 'assigned';
-    const STATE_CLOSED = 'closed';
+    public const STATE_CREATED = 'created';
+    public const STATE_OPENED = 'opened';
+    public const STATE_ASSIGNED = 'assigned';
+    public const STATE_CLOSED = 'closed';
 
     private string $state;
 
diff --git a/Behavioral/Memento/Tests/MementoTest.php b/Behavioral/Memento/Tests/MementoTest.php
index 9870bde..49145d9 100644
--- a/Behavioral/Memento/Tests/MementoTest.php
+++ b/Behavioral/Memento/Tests/MementoTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Memento\Tests;
 
diff --git a/Behavioral/Memento/Ticket.php b/Behavioral/Memento/Ticket.php
index 454f94e..676a239 100644
--- a/Behavioral/Memento/Ticket.php
+++ b/Behavioral/Memento/Ticket.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Memento;
 
diff --git a/Behavioral/NullObject/Logger.php b/Behavioral/NullObject/Logger.php
index 4e66df1..294c867 100644
--- a/Behavioral/NullObject/Logger.php
+++ b/Behavioral/NullObject/Logger.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\NullObject;
 
diff --git a/Behavioral/NullObject/NullLogger.php b/Behavioral/NullObject/NullLogger.php
index 7e3b03f..5ac15f3 100644
--- a/Behavioral/NullObject/NullLogger.php
+++ b/Behavioral/NullObject/NullLogger.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\NullObject;
 
diff --git a/Behavioral/NullObject/PrintLogger.php b/Behavioral/NullObject/PrintLogger.php
index e8d54bc..7e26c48 100644
--- a/Behavioral/NullObject/PrintLogger.php
+++ b/Behavioral/NullObject/PrintLogger.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\NullObject;
 
diff --git a/Behavioral/NullObject/Service.php b/Behavioral/NullObject/Service.php
index dc3183e..178f619 100644
--- a/Behavioral/NullObject/Service.php
+++ b/Behavioral/NullObject/Service.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\NullObject;
 
@@ -14,6 +16,6 @@ class Service
     public function doSomething()
     {
         // notice here that you don't have to check if the logger is set with eg. is_null(), instead just use it
-        $this->logger->log('We are in '.__METHOD__);
+        $this->logger->log('We are in ' . __METHOD__);
     }
 }
diff --git a/Behavioral/NullObject/Tests/LoggerTest.php b/Behavioral/NullObject/Tests/LoggerTest.php
index 5967494..0cd1552 100644
--- a/Behavioral/NullObject/Tests/LoggerTest.php
+++ b/Behavioral/NullObject/Tests/LoggerTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\NullObject\Tests;
 
diff --git a/Behavioral/Observer/Tests/ObserverTest.php b/Behavioral/Observer/Tests/ObserverTest.php
index 87e8f90..2dbd577 100644
--- a/Behavioral/Observer/Tests/ObserverTest.php
+++ b/Behavioral/Observer/Tests/ObserverTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Observer\Tests;
 
diff --git a/Behavioral/Observer/User.php b/Behavioral/Observer/User.php
index 226da38..03cfce8 100644
--- a/Behavioral/Observer/User.php
+++ b/Behavioral/Observer/User.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Observer;
 
diff --git a/Behavioral/Observer/UserObserver.php b/Behavioral/Observer/UserObserver.php
index 2630648..493d14a 100644
--- a/Behavioral/Observer/UserObserver.php
+++ b/Behavioral/Observer/UserObserver.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Observer;
 
diff --git a/Behavioral/Specification/AndSpecification.php b/Behavioral/Specification/AndSpecification.php
index 19b240d..2af44eb 100644
--- a/Behavioral/Specification/AndSpecification.php
+++ b/Behavioral/Specification/AndSpecification.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Specification;
 
diff --git a/Behavioral/Specification/Item.php b/Behavioral/Specification/Item.php
index efa537d..a1aa64d 100644
--- a/Behavioral/Specification/Item.php
+++ b/Behavioral/Specification/Item.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Specification;
 
diff --git a/Behavioral/Specification/NotSpecification.php b/Behavioral/Specification/NotSpecification.php
index f653cb3..8867655 100644
--- a/Behavioral/Specification/NotSpecification.php
+++ b/Behavioral/Specification/NotSpecification.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Specification;
 
diff --git a/Behavioral/Specification/OrSpecification.php b/Behavioral/Specification/OrSpecification.php
index 3f9c3b1..0ac338c 100644
--- a/Behavioral/Specification/OrSpecification.php
+++ b/Behavioral/Specification/OrSpecification.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Specification;
 
diff --git a/Behavioral/Specification/PriceSpecification.php b/Behavioral/Specification/PriceSpecification.php
index 9bb697a..3a19654 100644
--- a/Behavioral/Specification/PriceSpecification.php
+++ b/Behavioral/Specification/PriceSpecification.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Specification;
 
diff --git a/Behavioral/Specification/Specification.php b/Behavioral/Specification/Specification.php
index 7dda1b3..543c05c 100644
--- a/Behavioral/Specification/Specification.php
+++ b/Behavioral/Specification/Specification.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Specification;
 
diff --git a/Behavioral/Specification/Tests/SpecificationTest.php b/Behavioral/Specification/Tests/SpecificationTest.php
index 78852bb..e8823a4 100644
--- a/Behavioral/Specification/Tests/SpecificationTest.php
+++ b/Behavioral/Specification/Tests/SpecificationTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Specification\Tests;
 
diff --git a/Behavioral/State/OrderContext.php b/Behavioral/State/OrderContext.php
index e9ba539..c18961c 100644
--- a/Behavioral/State/OrderContext.php
+++ b/Behavioral/State/OrderContext.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\State;
 
diff --git a/Behavioral/State/State.php b/Behavioral/State/State.php
index 44fce7a..ed88495 100644
--- a/Behavioral/State/State.php
+++ b/Behavioral/State/State.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\State;
 
diff --git a/Behavioral/State/StateCreated.php b/Behavioral/State/StateCreated.php
index 6a6365f..22c184a 100644
--- a/Behavioral/State/StateCreated.php
+++ b/Behavioral/State/StateCreated.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\State;
 
diff --git a/Behavioral/State/StateDone.php b/Behavioral/State/StateDone.php
index 0fe0e3d..6ee3fde 100644
--- a/Behavioral/State/StateDone.php
+++ b/Behavioral/State/StateDone.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\State;
 
diff --git a/Behavioral/State/StateShipped.php b/Behavioral/State/StateShipped.php
index bfabbf0..d883413 100644
--- a/Behavioral/State/StateShipped.php
+++ b/Behavioral/State/StateShipped.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\State;
 
diff --git a/Behavioral/State/Tests/StateTest.php b/Behavioral/State/Tests/StateTest.php
index 307cb21..721efee 100644
--- a/Behavioral/State/Tests/StateTest.php
+++ b/Behavioral/State/Tests/StateTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\State\Tests;
 
diff --git a/Behavioral/Strategy/Comparator.php b/Behavioral/Strategy/Comparator.php
index 49b7e04..461c519 100644
--- a/Behavioral/Strategy/Comparator.php
+++ b/Behavioral/Strategy/Comparator.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Strategy;
 
diff --git a/Behavioral/Strategy/Context.php b/Behavioral/Strategy/Context.php
index e0c9b52..282e679 100644
--- a/Behavioral/Strategy/Context.php
+++ b/Behavioral/Strategy/Context.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Strategy;
 
diff --git a/Behavioral/Strategy/DateComparator.php b/Behavioral/Strategy/DateComparator.php
index 97346ec..2c361df 100644
--- a/Behavioral/Strategy/DateComparator.php
+++ b/Behavioral/Strategy/DateComparator.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Strategy;
 
diff --git a/Behavioral/Strategy/IdComparator.php b/Behavioral/Strategy/IdComparator.php
index f007f92..41a9610 100644
--- a/Behavioral/Strategy/IdComparator.php
+++ b/Behavioral/Strategy/IdComparator.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Strategy;
 
diff --git a/Behavioral/Strategy/Tests/StrategyTest.php b/Behavioral/Strategy/Tests/StrategyTest.php
index e19853b..336bbda 100644
--- a/Behavioral/Strategy/Tests/StrategyTest.php
+++ b/Behavioral/Strategy/Tests/StrategyTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Strategy\Tests;
 
diff --git a/Behavioral/TemplateMethod/BeachJourney.php b/Behavioral/TemplateMethod/BeachJourney.php
index f67f612..aa82eab 100644
--- a/Behavioral/TemplateMethod/BeachJourney.php
+++ b/Behavioral/TemplateMethod/BeachJourney.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\TemplateMethod;
 
diff --git a/Behavioral/TemplateMethod/CityJourney.php b/Behavioral/TemplateMethod/CityJourney.php
index 00fd7d5..fe1556d 100644
--- a/Behavioral/TemplateMethod/CityJourney.php
+++ b/Behavioral/TemplateMethod/CityJourney.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\TemplateMethod;
 
diff --git a/Behavioral/TemplateMethod/Journey.php b/Behavioral/TemplateMethod/Journey.php
index f83205a..95d3521 100644
--- a/Behavioral/TemplateMethod/Journey.php
+++ b/Behavioral/TemplateMethod/Journey.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\TemplateMethod;
 
diff --git a/Behavioral/TemplateMethod/Tests/JourneyTest.php b/Behavioral/TemplateMethod/Tests/JourneyTest.php
index c6245ef..66e7d4b 100644
--- a/Behavioral/TemplateMethod/Tests/JourneyTest.php
+++ b/Behavioral/TemplateMethod/Tests/JourneyTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\TemplateMethod\Tests;
 
diff --git a/Behavioral/Visitor/Group.php b/Behavioral/Visitor/Group.php
index dbf1cbd..43229d3 100644
--- a/Behavioral/Visitor/Group.php
+++ b/Behavioral/Visitor/Group.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Visitor;
 
diff --git a/Behavioral/Visitor/RecordingVisitor.php b/Behavioral/Visitor/RecordingVisitor.php
index 4854a16..011339b 100644
--- a/Behavioral/Visitor/RecordingVisitor.php
+++ b/Behavioral/Visitor/RecordingVisitor.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Visitor;
 
diff --git a/Behavioral/Visitor/Role.php b/Behavioral/Visitor/Role.php
index e31fdeb..6f4a948 100644
--- a/Behavioral/Visitor/Role.php
+++ b/Behavioral/Visitor/Role.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Visitor;
 
diff --git a/Behavioral/Visitor/RoleVisitor.php b/Behavioral/Visitor/RoleVisitor.php
index 339fa12..04d98b9 100644
--- a/Behavioral/Visitor/RoleVisitor.php
+++ b/Behavioral/Visitor/RoleVisitor.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Visitor;
 
diff --git a/Behavioral/Visitor/Tests/VisitorTest.php b/Behavioral/Visitor/Tests/VisitorTest.php
index 359a7be..443493d 100644
--- a/Behavioral/Visitor/Tests/VisitorTest.php
+++ b/Behavioral/Visitor/Tests/VisitorTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Tests\Visitor\Tests;
 
diff --git a/Behavioral/Visitor/User.php b/Behavioral/Visitor/User.php
index cfb06ed..df96bfe 100644
--- a/Behavioral/Visitor/User.php
+++ b/Behavioral/Visitor/User.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Behavioral\Visitor;
 
diff --git a/Creational/AbstractFactory/Tests/AbstractFactoryTest.php b/Creational/AbstractFactory/Tests/AbstractFactoryTest.php
index 400dc34..aa76a31 100644
--- a/Creational/AbstractFactory/Tests/AbstractFactoryTest.php
+++ b/Creational/AbstractFactory/Tests/AbstractFactoryTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\AbstractFactory\Tests;
 
diff --git a/Creational/Builder/Builder.php b/Creational/Builder/Builder.php
index b1c8c28..6bda440 100644
--- a/Creational/Builder/Builder.php
+++ b/Creational/Builder/Builder.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder;
 
diff --git a/Creational/Builder/CarBuilder.php b/Creational/Builder/CarBuilder.php
index 20badc7..b418004 100644
--- a/Creational/Builder/CarBuilder.php
+++ b/Creational/Builder/CarBuilder.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder;
 
diff --git a/Creational/Builder/Director.php b/Creational/Builder/Director.php
index db9b696..bf39aca 100644
--- a/Creational/Builder/Director.php
+++ b/Creational/Builder/Director.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder;
 
diff --git a/Creational/Builder/Parts/Car.php b/Creational/Builder/Parts/Car.php
index 6c78eb8..0ccd321 100644
--- a/Creational/Builder/Parts/Car.php
+++ b/Creational/Builder/Parts/Car.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder\Parts;
 
diff --git a/Creational/Builder/Parts/Door.php b/Creational/Builder/Parts/Door.php
index 94ca65e..302a4e8 100644
--- a/Creational/Builder/Parts/Door.php
+++ b/Creational/Builder/Parts/Door.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder\Parts;
 
diff --git a/Creational/Builder/Parts/Engine.php b/Creational/Builder/Parts/Engine.php
index 8799297..25371d4 100644
--- a/Creational/Builder/Parts/Engine.php
+++ b/Creational/Builder/Parts/Engine.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder\Parts;
 
diff --git a/Creational/Builder/Parts/Truck.php b/Creational/Builder/Parts/Truck.php
index 8759928..e3d7cd1 100644
--- a/Creational/Builder/Parts/Truck.php
+++ b/Creational/Builder/Parts/Truck.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder\Parts;
 
diff --git a/Creational/Builder/Parts/Vehicle.php b/Creational/Builder/Parts/Vehicle.php
index 1103be7..0cfb02c 100644
--- a/Creational/Builder/Parts/Vehicle.php
+++ b/Creational/Builder/Parts/Vehicle.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder\Parts;
 
diff --git a/Creational/Builder/Parts/Wheel.php b/Creational/Builder/Parts/Wheel.php
index d7ac041..1afffb4 100644
--- a/Creational/Builder/Parts/Wheel.php
+++ b/Creational/Builder/Parts/Wheel.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder\Parts;
 
diff --git a/Creational/Builder/Tests/DirectorTest.php b/Creational/Builder/Tests/DirectorTest.php
index 9cce577..7c20a90 100644
--- a/Creational/Builder/Tests/DirectorTest.php
+++ b/Creational/Builder/Tests/DirectorTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder\Tests;
 
diff --git a/Creational/Builder/TruckBuilder.php b/Creational/Builder/TruckBuilder.php
index fa41ed1..2be7f4e 100644
--- a/Creational/Builder/TruckBuilder.php
+++ b/Creational/Builder/TruckBuilder.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Builder;
 
diff --git a/Creational/FactoryMethod/FileLogger.php b/Creational/FactoryMethod/FileLogger.php
index fde47ee..2be2342 100644
--- a/Creational/FactoryMethod/FileLogger.php
+++ b/Creational/FactoryMethod/FileLogger.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\FactoryMethod;
 
diff --git a/Creational/FactoryMethod/FileLoggerFactory.php b/Creational/FactoryMethod/FileLoggerFactory.php
index a94598d..c5eb46d 100644
--- a/Creational/FactoryMethod/FileLoggerFactory.php
+++ b/Creational/FactoryMethod/FileLoggerFactory.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\FactoryMethod;
 
diff --git a/Creational/FactoryMethod/Logger.php b/Creational/FactoryMethod/Logger.php
index 8d1f451..b372cd0 100644
--- a/Creational/FactoryMethod/Logger.php
+++ b/Creational/FactoryMethod/Logger.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\FactoryMethod;
 
diff --git a/Creational/FactoryMethod/LoggerFactory.php b/Creational/FactoryMethod/LoggerFactory.php
index 5e5c54e..491e33f 100644
--- a/Creational/FactoryMethod/LoggerFactory.php
+++ b/Creational/FactoryMethod/LoggerFactory.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\FactoryMethod;
 
diff --git a/Creational/FactoryMethod/StdoutLogger.php b/Creational/FactoryMethod/StdoutLogger.php
index 84ccbeb..4e344ee 100644
--- a/Creational/FactoryMethod/StdoutLogger.php
+++ b/Creational/FactoryMethod/StdoutLogger.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\FactoryMethod;
 
diff --git a/Creational/FactoryMethod/StdoutLoggerFactory.php b/Creational/FactoryMethod/StdoutLoggerFactory.php
index fefe43c..293fdf6 100644
--- a/Creational/FactoryMethod/StdoutLoggerFactory.php
+++ b/Creational/FactoryMethod/StdoutLoggerFactory.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\FactoryMethod;
 
diff --git a/Creational/FactoryMethod/Tests/FactoryMethodTest.php b/Creational/FactoryMethod/Tests/FactoryMethodTest.php
index 85768db..a3db56c 100644
--- a/Creational/FactoryMethod/Tests/FactoryMethodTest.php
+++ b/Creational/FactoryMethod/Tests/FactoryMethodTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\FactoryMethod\Tests;
 
diff --git a/Creational/Pool/StringReverseWorker.php b/Creational/Pool/StringReverseWorker.php
index ca7a5f9..a2de032 100644
--- a/Creational/Pool/StringReverseWorker.php
+++ b/Creational/Pool/StringReverseWorker.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Pool;
 
diff --git a/Creational/Pool/Tests/PoolTest.php b/Creational/Pool/Tests/PoolTest.php
index aa74947..bf9b25b 100644
--- a/Creational/Pool/Tests/PoolTest.php
+++ b/Creational/Pool/Tests/PoolTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Pool\Tests;
 
diff --git a/Creational/Pool/WorkerPool.php b/Creational/Pool/WorkerPool.php
index be2ebf9..82426a9 100644
--- a/Creational/Pool/WorkerPool.php
+++ b/Creational/Pool/WorkerPool.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Pool;
 
diff --git a/Creational/Prototype/BarBookPrototype.php b/Creational/Prototype/BarBookPrototype.php
index b9257d3..6754d5d 100644
--- a/Creational/Prototype/BarBookPrototype.php
+++ b/Creational/Prototype/BarBookPrototype.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Prototype;
 
diff --git a/Creational/Prototype/BookPrototype.php b/Creational/Prototype/BookPrototype.php
index accd898..ff7b8d9 100644
--- a/Creational/Prototype/BookPrototype.php
+++ b/Creational/Prototype/BookPrototype.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Prototype;
 
diff --git a/Creational/Prototype/FooBookPrototype.php b/Creational/Prototype/FooBookPrototype.php
index d7a089b..842b160 100644
--- a/Creational/Prototype/FooBookPrototype.php
+++ b/Creational/Prototype/FooBookPrototype.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Prototype;
 
diff --git a/Creational/Prototype/Tests/PrototypeTest.php b/Creational/Prototype/Tests/PrototypeTest.php
index 2d04375..7f0a3ba 100644
--- a/Creational/Prototype/Tests/PrototypeTest.php
+++ b/Creational/Prototype/Tests/PrototypeTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Prototype\Tests;
 
diff --git a/Creational/SimpleFactory/Bicycle.php b/Creational/SimpleFactory/Bicycle.php
index ac985ec..e22d254 100644
--- a/Creational/SimpleFactory/Bicycle.php
+++ b/Creational/SimpleFactory/Bicycle.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\SimpleFactory;
 
diff --git a/Creational/SimpleFactory/SimpleFactory.php b/Creational/SimpleFactory/SimpleFactory.php
index 5298e10..1628f45 100644
--- a/Creational/SimpleFactory/SimpleFactory.php
+++ b/Creational/SimpleFactory/SimpleFactory.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\SimpleFactory;
 
diff --git a/Creational/SimpleFactory/Tests/SimpleFactoryTest.php b/Creational/SimpleFactory/Tests/SimpleFactoryTest.php
index 39bb573..f02fff2 100644
--- a/Creational/SimpleFactory/Tests/SimpleFactoryTest.php
+++ b/Creational/SimpleFactory/Tests/SimpleFactoryTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\SimpleFactory\Tests;
 
diff --git a/Creational/Singleton/Singleton.php b/Creational/Singleton/Singleton.php
index d4ea3a2..6215040 100644
--- a/Creational/Singleton/Singleton.php
+++ b/Creational/Singleton/Singleton.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Singleton;
 
@@ -34,7 +36,7 @@ final class Singleton
     private function __clone()
     {
     }
-    
+
     /**
      * prevent from being unserialized (which would create a second instance of it)
      */
diff --git a/Creational/Singleton/Tests/SingletonTest.php b/Creational/Singleton/Tests/SingletonTest.php
index 09b2434..95e8f5d 100644
--- a/Creational/Singleton/Tests/SingletonTest.php
+++ b/Creational/Singleton/Tests/SingletonTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\Singleton\Tests;
 
diff --git a/Creational/StaticFactory/FormatNumber.php b/Creational/StaticFactory/FormatNumber.php
index c6231e0..b7c1f63 100644
--- a/Creational/StaticFactory/FormatNumber.php
+++ b/Creational/StaticFactory/FormatNumber.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\StaticFactory;
 
diff --git a/Creational/StaticFactory/FormatString.php b/Creational/StaticFactory/FormatString.php
index 5574c0b..3f05bf9 100644
--- a/Creational/StaticFactory/FormatString.php
+++ b/Creational/StaticFactory/FormatString.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\StaticFactory;
 
diff --git a/Creational/StaticFactory/Formatter.php b/Creational/StaticFactory/Formatter.php
index 74e4f3e..9ce175d 100644
--- a/Creational/StaticFactory/Formatter.php
+++ b/Creational/StaticFactory/Formatter.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\StaticFactory;
 
diff --git a/Creational/StaticFactory/StaticFactory.php b/Creational/StaticFactory/StaticFactory.php
index 73db8a5..8ebff07 100644
--- a/Creational/StaticFactory/StaticFactory.php
+++ b/Creational/StaticFactory/StaticFactory.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\StaticFactory;
 
diff --git a/Creational/StaticFactory/Tests/StaticFactoryTest.php b/Creational/StaticFactory/Tests/StaticFactoryTest.php
index 00fcfe6..e3d567e 100644
--- a/Creational/StaticFactory/Tests/StaticFactoryTest.php
+++ b/Creational/StaticFactory/Tests/StaticFactoryTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Creational\StaticFactory\Tests;
 
diff --git a/More/EAV/Attribute.php b/More/EAV/Attribute.php
index 726c3f7..46ba9f4 100644
--- a/More/EAV/Attribute.php
+++ b/More/EAV/Attribute.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\EAV;
 
diff --git a/More/EAV/Entity.php b/More/EAV/Entity.php
index c6e49a6..1a619e1 100644
--- a/More/EAV/Entity.php
+++ b/More/EAV/Entity.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\EAV;
 
diff --git a/More/EAV/Tests/EAVTest.php b/More/EAV/Tests/EAVTest.php
index 79e9ac9..12b4efc 100644
--- a/More/EAV/Tests/EAVTest.php
+++ b/More/EAV/Tests/EAVTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\EAV\Tests;
 
diff --git a/More/EAV/Value.php b/More/EAV/Value.php
index b55eb4e..ef31882 100644
--- a/More/EAV/Value.php
+++ b/More/EAV/Value.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\EAV;
 
diff --git a/More/Repository/Domain/Post.php b/More/Repository/Domain/Post.php
index c67e1ac..4d8fbff 100644
--- a/More/Repository/Domain/Post.php
+++ b/More/Repository/Domain/Post.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\Repository\Domain;
 
diff --git a/More/Repository/Domain/PostId.php b/More/Repository/Domain/PostId.php
index 04b7b9b..8322cad 100644
--- a/More/Repository/Domain/PostId.php
+++ b/More/Repository/Domain/PostId.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\Repository\Domain;
 
diff --git a/More/Repository/Domain/PostStatus.php b/More/Repository/Domain/PostStatus.php
index fa81917..7db03a9 100644
--- a/More/Repository/Domain/PostStatus.php
+++ b/More/Repository/Domain/PostStatus.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\Repository\Domain;
 
@@ -10,11 +12,11 @@ use InvalidArgumentException;
  */
 class PostStatus
 {
-    const STATE_DRAFT_ID = 1;
-    const STATE_PUBLISHED_ID = 2;
+    public const STATE_DRAFT_ID = 1;
+    public const STATE_PUBLISHED_ID = 2;
 
-    const STATE_DRAFT = 'draft';
-    const STATE_PUBLISHED = 'published';
+    public const STATE_DRAFT = 'draft';
+    public const STATE_PUBLISHED = 'published';
 
     private static array $validStates = [
         self::STATE_DRAFT_ID => self::STATE_DRAFT,
diff --git a/More/Repository/InMemoryPersistence.php b/More/Repository/InMemoryPersistence.php
index 33b4adb..fc565ef 100644
--- a/More/Repository/InMemoryPersistence.php
+++ b/More/Repository/InMemoryPersistence.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\Repository;
 
diff --git a/More/Repository/Persistence.php b/More/Repository/Persistence.php
index b1e3e26..4aef4ea 100644
--- a/More/Repository/Persistence.php
+++ b/More/Repository/Persistence.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\Repository;
 
diff --git a/More/Repository/PostRepository.php b/More/Repository/PostRepository.php
index cc5d8a2..aaeb813 100644
--- a/More/Repository/PostRepository.php
+++ b/More/Repository/PostRepository.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\Repository;
 
diff --git a/More/Repository/Tests/PostRepositoryTest.php b/More/Repository/Tests/PostRepositoryTest.php
index 3270edb..6e72e92 100644
--- a/More/Repository/Tests/PostRepositoryTest.php
+++ b/More/Repository/Tests/PostRepositoryTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\Repository\Tests;
 
diff --git a/More/ServiceLocator/LogService.php b/More/ServiceLocator/LogService.php
index 1653a0b..5f3f5d8 100644
--- a/More/ServiceLocator/LogService.php
+++ b/More/ServiceLocator/LogService.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\ServiceLocator;
 
diff --git a/More/ServiceLocator/ServiceLocator.php b/More/ServiceLocator/ServiceLocator.php
index ff46c87..af2c861 100644
--- a/More/ServiceLocator/ServiceLocator.php
+++ b/More/ServiceLocator/ServiceLocator.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\ServiceLocator;
 
diff --git a/More/ServiceLocator/Tests/ServiceLocatorTest.php b/More/ServiceLocator/Tests/ServiceLocatorTest.php
index f43aec6..b8b1644 100644
--- a/More/ServiceLocator/Tests/ServiceLocatorTest.php
+++ b/More/ServiceLocator/Tests/ServiceLocatorTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\More\ServiceLocator\Tests;
 
diff --git a/Structural/Adapter/Book.php b/Structural/Adapter/Book.php
index 88ce1ad..59c11f5 100644
--- a/Structural/Adapter/Book.php
+++ b/Structural/Adapter/Book.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Adapter;
 
diff --git a/Structural/Adapter/EBook.php b/Structural/Adapter/EBook.php
index a858cf8..27c82b3 100644
--- a/Structural/Adapter/EBook.php
+++ b/Structural/Adapter/EBook.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Adapter;
 
diff --git a/Structural/Adapter/EBookAdapter.php b/Structural/Adapter/EBookAdapter.php
index e05f512..3c9515a 100644
--- a/Structural/Adapter/EBookAdapter.php
+++ b/Structural/Adapter/EBookAdapter.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Adapter;
 
diff --git a/Structural/Adapter/Kindle.php b/Structural/Adapter/Kindle.php
index ab9fced..4d42990 100644
--- a/Structural/Adapter/Kindle.php
+++ b/Structural/Adapter/Kindle.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Adapter;
 
diff --git a/Structural/Adapter/PaperBook.php b/Structural/Adapter/PaperBook.php
index c9ebf35..318d4ec 100644
--- a/Structural/Adapter/PaperBook.php
+++ b/Structural/Adapter/PaperBook.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Adapter;
 
diff --git a/Structural/Adapter/Tests/AdapterTest.php b/Structural/Adapter/Tests/AdapterTest.php
index 6e5de56..719df26 100644
--- a/Structural/Adapter/Tests/AdapterTest.php
+++ b/Structural/Adapter/Tests/AdapterTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Adapter\Tests;
 
diff --git a/Structural/Bridge/Formatter.php b/Structural/Bridge/Formatter.php
index 093dd39..13130de 100644
--- a/Structural/Bridge/Formatter.php
+++ b/Structural/Bridge/Formatter.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Bridge;
 
diff --git a/Structural/Bridge/HelloWorldService.php b/Structural/Bridge/HelloWorldService.php
index 10202ab..c606275 100644
--- a/Structural/Bridge/HelloWorldService.php
+++ b/Structural/Bridge/HelloWorldService.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Bridge;
 
diff --git a/Structural/Bridge/HtmlFormatter.php b/Structural/Bridge/HtmlFormatter.php
index b2f0a3a..1ecc17e 100644
--- a/Structural/Bridge/HtmlFormatter.php
+++ b/Structural/Bridge/HtmlFormatter.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Bridge;
 
diff --git a/Structural/Bridge/PingService.php b/Structural/Bridge/PingService.php
index f569ce6..6bc3105 100644
--- a/Structural/Bridge/PingService.php
+++ b/Structural/Bridge/PingService.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Bridge;
 
diff --git a/Structural/Bridge/PlainTextFormatter.php b/Structural/Bridge/PlainTextFormatter.php
index f7c5935..dd41e4e 100644
--- a/Structural/Bridge/PlainTextFormatter.php
+++ b/Structural/Bridge/PlainTextFormatter.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Bridge;
 
diff --git a/Structural/Bridge/Service.php b/Structural/Bridge/Service.php
index 360f007..b077fb0 100644
--- a/Structural/Bridge/Service.php
+++ b/Structural/Bridge/Service.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Bridge;
 
diff --git a/Structural/Bridge/Tests/BridgeTest.php b/Structural/Bridge/Tests/BridgeTest.php
index fa05821..fb589ec 100644
--- a/Structural/Bridge/Tests/BridgeTest.php
+++ b/Structural/Bridge/Tests/BridgeTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Bridge\Tests;
 
diff --git a/Structural/Composite/Form.php b/Structural/Composite/Form.php
index bec1ccb..7a72dff 100644
--- a/Structural/Composite/Form.php
+++ b/Structural/Composite/Form.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Composite;
 
diff --git a/Structural/Composite/InputElement.php b/Structural/Composite/InputElement.php
index 1ea4dc3..d9766b5 100644
--- a/Structural/Composite/InputElement.php
+++ b/Structural/Composite/InputElement.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Composite;
 
diff --git a/Structural/Composite/Renderable.php b/Structural/Composite/Renderable.php
index 1ec8eaf..fd993a1 100644
--- a/Structural/Composite/Renderable.php
+++ b/Structural/Composite/Renderable.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Composite;
 
diff --git a/Structural/Composite/Tests/CompositeTest.php b/Structural/Composite/Tests/CompositeTest.php
index e7546fa..e28c6e8 100644
--- a/Structural/Composite/Tests/CompositeTest.php
+++ b/Structural/Composite/Tests/CompositeTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Composite\Tests;
 
diff --git a/Structural/Composite/TextElement.php b/Structural/Composite/TextElement.php
index 4e9ad90..1411139 100644
--- a/Structural/Composite/TextElement.php
+++ b/Structural/Composite/TextElement.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Composite;
 
diff --git a/Structural/DataMapper/StorageAdapter.php b/Structural/DataMapper/StorageAdapter.php
index b7f04da..a34e058 100644
--- a/Structural/DataMapper/StorageAdapter.php
+++ b/Structural/DataMapper/StorageAdapter.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\DataMapper;
 
diff --git a/Structural/DataMapper/Tests/DataMapperTest.php b/Structural/DataMapper/Tests/DataMapperTest.php
index 07253ca..0f0ed50 100644
--- a/Structural/DataMapper/Tests/DataMapperTest.php
+++ b/Structural/DataMapper/Tests/DataMapperTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\DataMapper\Tests;
 
diff --git a/Structural/DataMapper/User.php b/Structural/DataMapper/User.php
index 144a0dc..6671385 100644
--- a/Structural/DataMapper/User.php
+++ b/Structural/DataMapper/User.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\DataMapper;
 
diff --git a/Structural/DataMapper/UserMapper.php b/Structural/DataMapper/UserMapper.php
index c3af100..ebdbc55 100644
--- a/Structural/DataMapper/UserMapper.php
+++ b/Structural/DataMapper/UserMapper.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\DataMapper;
 
diff --git a/Structural/Decorator/Booking.php b/Structural/Decorator/Booking.php
index 16e766c..6bc9fc9 100644
--- a/Structural/Decorator/Booking.php
+++ b/Structural/Decorator/Booking.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Decorator;
 
diff --git a/Structural/Decorator/BookingDecorator.php b/Structural/Decorator/BookingDecorator.php
index d2ce76e..75ef789 100644
--- a/Structural/Decorator/BookingDecorator.php
+++ b/Structural/Decorator/BookingDecorator.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Decorator;
 
diff --git a/Structural/Decorator/DoubleRoomBooking.php b/Structural/Decorator/DoubleRoomBooking.php
index 462fb66..d70503c 100644
--- a/Structural/Decorator/DoubleRoomBooking.php
+++ b/Structural/Decorator/DoubleRoomBooking.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Decorator;
 
diff --git a/Structural/Decorator/ExtraBed.php b/Structural/Decorator/ExtraBed.php
index f7a01e7..ea248fa 100644
--- a/Structural/Decorator/ExtraBed.php
+++ b/Structural/Decorator/ExtraBed.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Decorator;
 
diff --git a/Structural/Decorator/Tests/DecoratorTest.php b/Structural/Decorator/Tests/DecoratorTest.php
index 3900936..9cec20d 100644
--- a/Structural/Decorator/Tests/DecoratorTest.php
+++ b/Structural/Decorator/Tests/DecoratorTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Decorator\Tests;
 
diff --git a/Structural/Decorator/WiFi.php b/Structural/Decorator/WiFi.php
index 58d4036..5f10e28 100644
--- a/Structural/Decorator/WiFi.php
+++ b/Structural/Decorator/WiFi.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Decorator;
 
diff --git a/Structural/DependencyInjection/DatabaseConfiguration.php b/Structural/DependencyInjection/DatabaseConfiguration.php
index 2713e0c..e7da358 100644
--- a/Structural/DependencyInjection/DatabaseConfiguration.php
+++ b/Structural/DependencyInjection/DatabaseConfiguration.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\DependencyInjection;
 
diff --git a/Structural/DependencyInjection/DatabaseConnection.php b/Structural/DependencyInjection/DatabaseConnection.php
index a63f91a..9c11768 100644
--- a/Structural/DependencyInjection/DatabaseConnection.php
+++ b/Structural/DependencyInjection/DatabaseConnection.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\DependencyInjection;
 
diff --git a/Structural/DependencyInjection/Tests/DependencyInjectionTest.php b/Structural/DependencyInjection/Tests/DependencyInjectionTest.php
index 75cdd71..e9cc6c1 100644
--- a/Structural/DependencyInjection/Tests/DependencyInjectionTest.php
+++ b/Structural/DependencyInjection/Tests/DependencyInjectionTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\DependencyInjection\Tests;
 
diff --git a/Structural/Facade/Bios.php b/Structural/Facade/Bios.php
index 6c1a59a..11e410c 100644
--- a/Structural/Facade/Bios.php
+++ b/Structural/Facade/Bios.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Facade;
 
diff --git a/Structural/Facade/Facade.php b/Structural/Facade/Facade.php
index 4f41cef..ff4e24a 100644
--- a/Structural/Facade/Facade.php
+++ b/Structural/Facade/Facade.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Facade;
 
diff --git a/Structural/Facade/OperatingSystem.php b/Structural/Facade/OperatingSystem.php
index 66d0c85..c5a9127 100644
--- a/Structural/Facade/OperatingSystem.php
+++ b/Structural/Facade/OperatingSystem.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Facade;
 
diff --git a/Structural/Facade/Tests/FacadeTest.php b/Structural/Facade/Tests/FacadeTest.php
index 452ca66..ebeb478 100644
--- a/Structural/Facade/Tests/FacadeTest.php
+++ b/Structural/Facade/Tests/FacadeTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Facade\Tests;
 
diff --git a/Structural/FluentInterface/Sql.php b/Structural/FluentInterface/Sql.php
index 1056116..7b250ed 100644
--- a/Structural/FluentInterface/Sql.php
+++ b/Structural/FluentInterface/Sql.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\FluentInterface;
 
@@ -17,7 +19,7 @@ class Sql implements \Stringable
 
     public function from(string $table, string $alias): Sql
     {
-        $this->from[] = $table.' AS '.$alias;
+        $this->from[] = $table . ' AS ' . $alias;
 
         return $this;
     }
diff --git a/Structural/FluentInterface/Tests/FluentInterfaceTest.php b/Structural/FluentInterface/Tests/FluentInterfaceTest.php
index fb0010d..59a8fe5 100644
--- a/Structural/FluentInterface/Tests/FluentInterfaceTest.php
+++ b/Structural/FluentInterface/Tests/FluentInterfaceTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\FluentInterface\Tests;
 
diff --git a/Structural/Flyweight/Character.php b/Structural/Flyweight/Character.php
index 65b6ea0..3515661 100644
--- a/Structural/Flyweight/Character.php
+++ b/Structural/Flyweight/Character.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Flyweight;
 
diff --git a/Structural/Flyweight/Tests/FlyweightTest.php b/Structural/Flyweight/Tests/FlyweightTest.php
index 0f9959b..16fb7b8 100644
--- a/Structural/Flyweight/Tests/FlyweightTest.php
+++ b/Structural/Flyweight/Tests/FlyweightTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Flyweight\Tests;
 
diff --git a/Structural/Flyweight/Text.php b/Structural/Flyweight/Text.php
index 20bf738..9dc69bd 100644
--- a/Structural/Flyweight/Text.php
+++ b/Structural/Flyweight/Text.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Flyweight;
 
diff --git a/Structural/Flyweight/TextFactory.php b/Structural/Flyweight/TextFactory.php
index 7eb6e20..db1402f 100644
--- a/Structural/Flyweight/TextFactory.php
+++ b/Structural/Flyweight/TextFactory.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Flyweight;
 
diff --git a/Structural/Proxy/BankAccount.php b/Structural/Proxy/BankAccount.php
index e10a3cc..ef771dc 100644
--- a/Structural/Proxy/BankAccount.php
+++ b/Structural/Proxy/BankAccount.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Proxy;
 
diff --git a/Structural/Proxy/BankAccountProxy.php b/Structural/Proxy/BankAccountProxy.php
index 3ec229e..ab50629 100644
--- a/Structural/Proxy/BankAccountProxy.php
+++ b/Structural/Proxy/BankAccountProxy.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Proxy;
 
diff --git a/Structural/Proxy/HeavyBankAccount.php b/Structural/Proxy/HeavyBankAccount.php
index 6b5a23e..6b8ec4d 100644
--- a/Structural/Proxy/HeavyBankAccount.php
+++ b/Structural/Proxy/HeavyBankAccount.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Proxy;
 
diff --git a/Structural/Proxy/Tests/ProxyTest.php b/Structural/Proxy/Tests/ProxyTest.php
index 8ecb753..ab108a6 100644
--- a/Structural/Proxy/Tests/ProxyTest.php
+++ b/Structural/Proxy/Tests/ProxyTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Proxy\Tests;
 
diff --git a/Structural/Registry/Registry.php b/Structural/Registry/Registry.php
index e37b217..84878a8 100644
--- a/Structural/Registry/Registry.php
+++ b/Structural/Registry/Registry.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Registry;
 
@@ -6,7 +8,7 @@ use InvalidArgumentException;
 
 abstract class Registry
 {
-    const LOGGER = 'logger';
+    public const LOGGER = 'logger';
 
     /**
      * this introduces global state in your application which can not be mocked up for testing
diff --git a/Structural/Registry/Tests/RegistryTest.php b/Structural/Registry/Tests/RegistryTest.php
index 100170b..aae90aa 100644
--- a/Structural/Registry/Tests/RegistryTest.php
+++ b/Structural/Registry/Tests/RegistryTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace DesignPatterns\Structural\Registry\Tests;
 
diff --git a/composer.json b/composer.json
index 1c2f199..5f2108b 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,6 @@
     "require-dev": {
         "phpunit/phpunit": "^9",
         "squizlabs/php_codesniffer": "^3",
-        "flyeralarm/php-code-validator": "^2.2",
         "vimeo/psalm": "^4",
         "psalm/plugin-phpunit": "*",
         "rector/rector": "*"
diff --git a/composer.lock b/composer.lock
index 3ad8bb9..ac819e1 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "40404fe777c8f5e94a46511a604ee3dc",
+    "content-hash": "c660894bd4b5a538c9d0e6a7a9151c24",
     "packages": [
         {
             "name": "psr/http-message",
@@ -807,48 +807,6 @@
             },
             "time": "2021-02-22T14:02:09+00:00"
         },
-        {
-            "name": "flyeralarm/php-code-validator",
-            "version": "2.3.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/flyeralarm/php-code-validator.git",
-                "reference": "2db2ce13e36ee13567fdbf42cc464264166025b8"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/flyeralarm/php-code-validator/zipball/2db2ce13e36ee13567fdbf42cc464264166025b8",
-                "reference": "2db2ce13e36ee13567fdbf42cc464264166025b8",
-                "shasum": ""
-            },
-            "require": {
-                "squizlabs/php_codesniffer": "^3.0"
-            },
-            "bin": [
-                "bin/php-code-validator"
-            ],
-            "type": "config",
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Daniel Müller",
-                    "email": "daniel.mueller@flyeralarm.com"
-                },
-                {
-                    "name": "Maximilian Grosch",
-                    "email": "maximilian.grosch@flyeralarm.com"
-                }
-            ],
-            "description": "A custom coding standard for FLYERALARM",
-            "support": {
-                "issues": "https://github.com/flyeralarm/php-code-validator/issues",
-                "source": "https://github.com/flyeralarm/php-code-validator/tree/2.3.0"
-            },
-            "time": "2020-10-02T09:10:58+00:00"
-        },
         {
             "name": "jean85/pretty-package-versions",
             "version": "2.0.3",
@@ -7015,5 +6973,5 @@
         "ext-json": "*"
     },
     "platform-dev": [],
-    "plugin-api-version": "2.0.0"
+    "plugin-api-version": "2.1.0"
 }
diff --git a/phpcs.xml.dist b/phpcs.xml.dist
index fef0afa..1b15b52 100644
--- a/phpcs.xml.dist
+++ b/phpcs.xml.dist
@@ -4,5 +4,5 @@
     <exclude-pattern>vendor</exclude-pattern>
     <arg value="sp"/>
 
-    <rule ref="vendor/flyeralarm/php-code-validator/ruleset.xml"/>
+    <rule ref="PSR12"/>
 </ruleset>