diff --git a/examples/tiles/city_tile.scad b/examples/tiles/city_tile.scad
new file mode 100644
index 00000000..3a344b00
--- /dev/null
+++ b/examples/tiles/city_tile.scad
@@ -0,0 +1,432 @@
+use <rounded_square.scad>;
+use <select.scad>;
+use <shear.scad>;
+use <shape_trapezium.scad>;
+use <arc.scad>;
+use <util/rand.scad>;
+
+module city_tile(i, tile_width = 30) {
+    select(i) {
+        tile00();
+        tile01();
+        tile02();
+        tile03();
+        tile04();
+        tile05();
+        tile06();
+        tile07();
+        tile08();
+        tile09();
+        tile10();
+        tile11();
+        tile12();
+        tile13();
+        tile14();
+        tile15();
+    }
+
+    // tiles, quick and dirty code
+    module base() {
+        tileW = 30;
+        h = 3;
+        linear_extrude(h)
+            square(tileW, center = true);
+
+        linear_extrude(h + .2)
+            rounded_square(tileW - 4, corner_r = 1, center = true, $fn = 24);
+    }
+
+    module pillar() {
+        tileW = 30;
+        roadW = 25 / 3;
+        halfRW = roadW / 2;
+        halfTW = tileW / 2;
+        
+        translate([0, halfTW / 1.6, 2.25])
+            linear_extrude(10)
+                rounded_square(halfRW / 1.25, corner_r = .8, center = true, $fn = 6);
+                
+        translate([0, halfTW / 1.6, 11.56])
+        rotate([90, 0, 0])
+        linear_extrude(halfRW / 1.225, center = true)
+            polygon(
+                shape_trapezium([halfRW / 1.25, roadW * 0.9], 
+                h = halfRW / 3,
+                corner_r = 0)
+            );
+    }
+
+    module long_buildings(h) {
+        module side_building0() {
+            linear_extrude(rand(10, h))
+                rounded_square([6, 23], corner_r = 1, center = true, $fn = rand(4, 12));
+        }
+
+        module side_building1() {
+            linear_extrude(rand(10, h))
+                rounded_square([6, 15], corner_r = 1, center = true, $fn = rand(4, 12));
+        }
+
+        module side_building2() {
+            translate([0, 5])
+            linear_extrude(rand(10, h))
+                rounded_square([6, 12], corner_r = 1, center = true, $fn = rand(4, 12));
+
+            translate([0, -7])
+            linear_extrude(rand(10, h))
+                rounded_square([6, 10], corner_r = 1, center = true, $fn = rand(4, 12));
+        }
+
+        module side_building3() {
+            translate([0, -6])
+            linear_extrude(rand(10, h))
+                rounded_square([6, 12], corner_r = 1, center = true, $fn = rand(4, 12));
+
+            translate([0, 6.5])
+            linear_extrude(rand(10, h))
+                rounded_square([6, 10], corner_r = 1, center = true, $fn = rand(4, 12));
+        }
+        
+        b = round(rand(0, 3));
+        if(b == 0) {
+            side_building0();
+        }
+        else if(b == 1) {
+            side_building1();
+        }
+        else if(b == 2) {
+            side_building2();
+        }
+        else if(b == 3) {
+            side_building3();
+        }
+    }
+
+    module short_buildings(h) {
+        linear_extrude(rand(4, h))
+            rounded_square(rand(3, 8), corner_r = .5, center = true, $fn = rand(4, 12));
+
+        linear_extrude(rand(5, h))
+            rounded_square(rand(3, 8), corner_r = .5, center = true, $fn = rand(4, 12));
+
+        linear_extrude(rand(5, h))
+            rounded_square(rand(3, 8), corner_r = .5, center = true, $fn = rand(4, 12)); 
+    }
+
+    module tile00() {
+        base();
+
+        f1 = rand(12.5, 25);
+        linear_extrude(f1)
+            rounded_square(rand(20, 22), corner_r = rand(0.1, 2), center = true);
+
+        f2 = rand(f1, 40);
+        linear_extrude(f2)
+            rounded_square(rand(17, 19), corner_r = rand(0.1, 2), center = true);
+            
+        f3 = rand(f2, 50);
+        linear_extrude(f3)
+            rounded_square(rand(10, 14), corner_r = rand(0.1, 2), center = true);
+            
+        linear_extrude(f3 + 2, scale = rand(0.1, 0.5))
+            square(20, center = true);
+    }
+
+    module tile01() {
+        tileW = 30;
+        roadW = 25 / 3;
+        roadL = tileW * 0.75;
+        halfRW = roadW / 2;
+        halfTW = tileW / 2;
+        
+        module road() {
+            translate([0, -halfTW / 2, 1])
+            shear(sz = [0, .5]){
+                translate([-halfRW, 0])
+                linear_extrude(2)
+                    square([roadW, roadL]);
+                
+                linear_extrude(3)
+                difference() {
+                    translate([-halfRW, 0])	
+                        square([roadW, roadL]);
+                        
+                    translate([-(roadW - 2) / 2, 0])	
+                        square([roadW - 2, roadL]);
+                }
+            }
+            
+
+            translate([0, 0, -1.2])
+            scale([1, 1, 0.9])
+                pillar();			
+        }
+        
+        module station() {
+            translate([0, -halfRW]) 
+            difference() {
+                linear_extrude(15, scale = rand(0.8, 1))
+                    rounded_square(roadW * 1.75, corner_r = rand(0.1, 2), center = true, $fn = round(rand(4, 24)));
+                
+                translate([0, halfRW])
+                linear_extrude(12.5)
+                    square([roadW * 1.1, roadW * 2], center = true);
+            }
+            
+            // top
+            topL = roadW * 1.75 * 0.8 ;
+            translate([0, -halfRW, 15])
+            linear_extrude(rand(1, 4), scale = rand(0.1, 1))
+                rounded_square(topL, corner_r = rand(0.1, topL / 2), center = true, $fn = round(rand(4, 6)));
+        }
+        
+        base();
+        color("LightYellow")
+		road();
+        station();
+        
+        translate([8.5, 0]) {
+            long_buildings(15);
+            short_buildings(20);
+        }
+            
+        translate([-8.5, 0]) {
+            long_buildings(15);
+            short_buildings(20);
+        }
+    }
+
+    module tile02() {
+        rotate(-90)
+        tile01();
+    }
+
+    module tile04() {
+        rotate(-180)
+        tile01();
+    }
+
+    module tile08() {
+        rotate(90)
+        tile01();
+    }
+
+    module tile03() {
+        tileW = 30;
+        roadW = 25 / 3;
+        roadL = tileW * 0.75;
+        halfRW = roadW / 2;
+        halfTW = tileW / 2;
+        
+        module road() {
+            translate([halfTW, halfTW, halfTW * 0.5 + 4.75]) {
+                linear_extrude(2)
+                    arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
+                    
+                linear_extrude(3)
+                    difference() {
+                        arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
+                        arc(radius = halfTW, angle = [180, 270], width = roadW - 2, $fn = 64);
+                    }
+            }			
+        }
+        
+        base();
+		color("LightYellow")
+        road();	
+        translate([1, 0, 0])
+            pillar();	
+        translate([0, 1, 0])
+        rotate(-90)
+            pillar();
+            
+        translate([-8.5, 0]) 
+            long_buildings(21);
+
+        rotate(90)
+        translate([-8.5, 0]) 
+            long_buildings(21);
+        
+        translate([8.5, 8.5]) 
+            short_buildings(12);
+    }
+
+    module tile06() {
+        rotate(-90)
+        tile03();
+    }
+
+    module tile09() {
+        rotate(90)
+        tile03();
+    }
+
+    module tile12() {
+        rotate(-180)
+        tile03();
+    }
+
+    module tile05() {
+        tileW = 30;
+        roadW = 25 / 3;
+        roadL = tileW;
+        halfRW = roadW / 2;
+        halfTW = tileW / 2;
+        
+        module road() {
+            translate([0, 0, halfTW * 0.5 + 4.75]) {
+                linear_extrude(2)
+                    square([roadW, roadL], center = true);
+                
+                linear_extrude(3)
+                difference() {
+                    square([roadW, roadL], center = true);
+                    square([roadW - 2, roadL], center = true);
+                }
+            }
+        }
+        
+        base();
+		color("LightYellow")
+        road();
+        pillar();
+        rotate(180)
+            pillar();
+        translate([0, -halfTW / 1.6, 0])
+            pillar();
+
+        translate([8.5, 0]) {
+            long_buildings(21);
+            short_buildings(21);
+        }
+        
+        translate([-8.5, 0]) {
+            long_buildings(21);
+            short_buildings(21);
+        }
+    }
+
+    module tile10() {
+        rotate(90)
+        tile05();
+    }
+
+    module tile15() {
+        module tile() {
+            tileW = 30;
+            roadW = 25 / 3;
+            roadL = tileW * 0.75;
+            halfRW = roadW / 2;
+            halfTW = tileW / 2;
+            
+            module road() {
+                translate([halfTW, halfTW, halfTW * 0.5 + 4.75]) {
+                    linear_extrude(2)
+                        arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
+                        
+                    linear_extrude(3)
+                        difference() {
+                            arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
+                            arc(radius = halfTW, angle = [180, 270], width = roadW - 2, $fn = 64);
+                        }
+                }				
+            }
+            
+            base();
+			color("LightYellow")
+            road();	
+            translate([1, 0, 0])
+                pillar();	
+            translate([0, 1, 0])
+            rotate(-90)
+                pillar();
+                
+            translate([8.5, 8.5]) 
+                short_buildings(12);
+                
+            translate([8.5, -8.5]) 
+                short_buildings(12);
+        }
+
+        rotate([0, 90][round(rand(0, 1))]) {
+            tile();
+            rotate(180)
+                tile();
+        }
+    }
+
+    module tile07() {
+        tileW = 30;
+        roadW = 25 / 3;
+        roadL = tileW * 0.75;
+        halfRW = roadW / 2;
+        halfTW = tileW / 2;
+        
+        module road() {
+            module road_shape() {
+                translate([halfTW, halfTW]) 
+                    arc(radius = halfTW, angle = [135, 295], width = roadW, $fn = 64);
+                mirror([0, 1, 0])
+                translate([halfTW, halfTW]) 
+                    arc(radius = halfTW, angle = [135, 295], width = roadW, $fn = 64);
+            }
+            
+            translate([0, 0, halfTW * 0.5 + 4.75]) {
+                linear_extrude(2)
+                intersection() {
+                    square(tileW, center = true);
+                    road_shape();
+                }
+                
+                linear_extrude(3)
+                intersection() {
+                    square(tileW, center = true);
+                    difference() {
+                        road_shape();
+                        offset(-1) 
+                            road_shape();
+                    }
+                }
+            }
+        }
+        
+        base();
+		color("LightYellow")
+        road();	
+
+        translate([1, 0, 0])
+            pillar();	
+        translate([0, 1, 0])
+        rotate(-90)
+            pillar();
+        mirror([0, 1, 0])
+        translate([0, 1, 0])
+            pillar();
+            
+        translate([-8.5, 0]) {
+            long_buildings(21);
+            short_buildings(21);
+        }
+        
+        translate([8.5, 8.5]) 
+            short_buildings(12);
+
+        translate([8.5, -8.5]) 
+            short_buildings(12);
+    }
+
+    module tile11() {
+        rotate(90)
+            tile07();
+    }
+
+    module tile13() {
+        rotate(180)
+            tile07();
+    }
+
+    module tile14() {
+        rotate(-90)
+            tile07();
+    }
+}
\ No newline at end of file
diff --git a/examples/tiles/maze_city.scad b/examples/tiles/maze_city.scad
index aab0af40..f9e1c590 100644
--- a/examples/tiles/maze_city.scad
+++ b/examples/tiles/maze_city.scad
@@ -1,14 +1,10 @@
 use <maze/mz_square_initialize.scad>;
 use <maze/mz_wang_tiles.scad>;
-use <rounded_square.scad>;
-use <shape_trapezium.scad>;
-use <arc.scad>;
-use <shear.scad>;
 use <util/rand.scad>;
-use <select.scad>;
+use <city_tile.scad>;
 
-rows = 20;
-columns = 20;
+rows = 10;
+columns = 10;
 skyscraper_prs = 0.05;
 
 maze_city(rows, columns, skyscraper_prs);
@@ -19,435 +15,16 @@ module maze_city(rows, columns, skyscraper_prs) {
 		rand() < skyscraper_prs ? 0 : 1]
 	];
 
+    tiles = mz_wang_tiles(
+        rows, columns, [0, 0], 
+        init_cells = mz_square_initialize(rows, columns, mask)
+    );
     tile_width = 30;
-    for(tile = mz_wang_tiles(rows, columns, [0, 0], init_cells = 
-mz_square_initialize(rows, columns, mask))) {
+    for(tile = tiles) {
         x = tile[0];
         y = tile[1];
         i = tile[2];
         translate([x, y] * tile_width)
-        select(i) {
-            tile00();
-            tile01();
-            tile02();
-            tile03();
-            tile04();
-            tile05();
-            tile06();
-            tile07();
-            tile08();
-            tile09();
-            tile10();
-            tile11();
-            tile12();
-            tile13();
-            tile14();
-            tile15();
-        }
-    }
-
-    // tiles, quick and dirty code
-    module base() {
-        tileW = 30;
-        h = 3;
-        linear_extrude(h)
-            square(tileW, center = true);
-
-        linear_extrude(h + .2)
-            rounded_square(tileW - 4, corner_r = 1, center = true, $fn = 24);
-    }
-
-    module pillar() {
-        tileW = 30;
-        roadW = 25 / 3;
-        halfRW = roadW / 2;
-        halfTW = tileW / 2;
-        
-        translate([0, halfTW / 1.6, 2.25])
-            linear_extrude(10)
-                rounded_square(halfRW / 1.25, corner_r = .8, center = true, $fn = 6);
-                
-        translate([0, halfTW / 1.6, 11.56])
-        rotate([90, 0, 0])
-        linear_extrude(halfRW / 1.225, center = true)
-            polygon(
-                shape_trapezium([halfRW / 1.25, roadW * 0.9], 
-                h = halfRW / 3,
-                corner_r = 0)
-            );
-    }
-
-    module long_buildings(h) {
-        module side_building0() {
-            linear_extrude(rand(10, h))
-                rounded_square([6, 23], corner_r = 1, center = true, $fn = rand(4, 12));
-        }
-
-        module side_building1() {
-            linear_extrude(rand(10, h))
-                rounded_square([6, 15], corner_r = 1, center = true, $fn = rand(4, 12));
-        }
-
-        module side_building2() {
-            translate([0, 5])
-            linear_extrude(rand(10, h))
-                rounded_square([6, 12], corner_r = 1, center = true, $fn = rand(4, 12));
-
-            translate([0, -7])
-            linear_extrude(rand(10, h))
-                rounded_square([6, 10], corner_r = 1, center = true, $fn = rand(4, 12));
-        }
-
-        module side_building3() {
-            translate([0, -6])
-            linear_extrude(rand(10, h))
-                rounded_square([6, 12], corner_r = 1, center = true, $fn = rand(4, 12));
-
-            translate([0, 6.5])
-            linear_extrude(rand(10, h))
-                rounded_square([6, 10], corner_r = 1, center = true, $fn = rand(4, 12));
-        }
-        
-        b = round(rand(0, 3));
-        if(b == 0) {
-            side_building0();
-        }
-        else if(b == 1) {
-            side_building1();
-        }
-        else if(b == 2) {
-            side_building2();
-        }
-        else if(b == 3) {
-            side_building3();
-        }
-    }
-
-    module short_buildings(h) {
-        linear_extrude(rand(4, h))
-            rounded_square(rand(3, 8), corner_r = .5, center = true, $fn = rand(4, 12));
-
-        linear_extrude(rand(5, h))
-            rounded_square(rand(3, 8), corner_r = .5, center = true, $fn = rand(4, 12));
-
-        linear_extrude(rand(5, h))
-            rounded_square(rand(3, 8), corner_r = .5, center = true, $fn = rand(4, 12)); 
-    }
-
-    module tile00() {
-        base();
-
-        f1 = rand(12.5, 25);
-        linear_extrude(f1)
-            rounded_square(rand(20, 22), corner_r = rand(0.1, 2), center = true);
-
-        f2 = rand(f1, 40);
-        linear_extrude(f2)
-            rounded_square(rand(17, 19), corner_r = rand(0.1, 2), center = true);
-            
-        f3 = rand(f2, 50);
-        linear_extrude(f3)
-            rounded_square(rand(10, 14), corner_r = rand(0.1, 2), center = true);
-            
-        linear_extrude(f3 + 2, scale = rand(0.1, 0.5))
-            square(20, center = true);
-    }
-
-    module tile01() {
-        tileW = 30;
-        roadW = 25 / 3;
-        roadL = tileW * 0.75;
-        halfRW = roadW / 2;
-        halfTW = tileW / 2;
-        
-        module road() {
-            translate([0, -halfTW / 2, 1])
-            shear(sz = [0, .5]){
-                translate([-halfRW, 0])
-                linear_extrude(2)
-                    square([roadW, roadL]);
-                
-                linear_extrude(3)
-                difference() {
-                    translate([-halfRW, 0])	
-                        square([roadW, roadL]);
-                        
-                    translate([-(roadW - 2) / 2, 0])	
-                        square([roadW - 2, roadL]);
-                }
-            }
-            
-
-            translate([0, 0, -1.2])
-            scale([1, 1, 0.9])
-                pillar();			
-        }
-        
-        module station() {
-            translate([0, -halfRW]) 
-            difference() {
-                linear_extrude(15, scale = rand(0.8, 1))
-                    rounded_square(roadW * 1.75, corner_r = rand(0.1, 2), center = true, $fn = round(rand(4, 24)));
-                
-                translate([0, halfRW])
-                linear_extrude(12.5)
-                    square([roadW * 1.1, roadW * 2], center = true);
-            }
-            
-            // top
-            topL = roadW * 1.75 * 0.8 ;
-            translate([0, -halfRW, 15])
-            linear_extrude(rand(1, 4), scale = rand(0.1, 1))
-                rounded_square(topL, corner_r = rand(0.1, topL / 2), center = true, $fn = round(rand(4, 6)));
-        }
-        
-        base();
-        color("LightYellow")
-		road();
-        station();
-        
-        translate([8.5, 0]) {
-            long_buildings(15);
-            short_buildings(20);
-        }
-            
-        translate([-8.5, 0]) {
-            long_buildings(15);
-            short_buildings(20);
-        }
-    }
-
-    module tile02() {
-        rotate(-90)
-        tile01();
-    }
-
-    module tile04() {
-        rotate(-180)
-        tile01();
-    }
-
-    module tile08() {
-        rotate(90)
-        tile01();
-    }
-
-    module tile03() {
-        tileW = 30;
-        roadW = 25 / 3;
-        roadL = tileW * 0.75;
-        halfRW = roadW / 2;
-        halfTW = tileW / 2;
-        
-        module road() {
-            translate([halfTW, halfTW, halfTW * 0.5 + 4.75]) {
-                linear_extrude(2)
-                    arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
-                    
-                linear_extrude(3)
-                    difference() {
-                        arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
-                        arc(radius = halfTW, angle = [180, 270], width = roadW - 2, $fn = 64);
-                    }
-            }			
-        }
-        
-        base();
-		color("LightYellow")
-        road();	
-        translate([1, 0, 0])
-            pillar();	
-        translate([0, 1, 0])
-        rotate(-90)
-            pillar();
-            
-        translate([-8.5, 0]) 
-            long_buildings(21);
-
-        rotate(90)
-        translate([-8.5, 0]) 
-            long_buildings(21);
-        
-        translate([8.5, 8.5]) 
-            short_buildings(12);
-    }
-
-    module tile06() {
-        rotate(-90)
-        tile03();
-    }
-
-    module tile09() {
-        rotate(90)
-        tile03();
-    }
-
-    module tile12() {
-        rotate(-180)
-        tile03();
-    }
-
-    module tile05() {
-        tileW = 30;
-        roadW = 25 / 3;
-        roadL = tileW;
-        halfRW = roadW / 2;
-        halfTW = tileW / 2;
-        
-        module road() {
-            translate([0, 0, halfTW * 0.5 + 4.75]) {
-                linear_extrude(2)
-                    square([roadW, roadL], center = true);
-                
-                linear_extrude(3)
-                difference() {
-                    square([roadW, roadL], center = true);
-                    square([roadW - 2, roadL], center = true);
-                }
-            }
-        }
-        
-        base();
-		color("LightYellow")
-        road();
-        pillar();
-        rotate(180)
-            pillar();
-        translate([0, -halfTW / 1.6, 0])
-            pillar();
-
-        translate([8.5, 0]) {
-            long_buildings(21);
-            short_buildings(21);
-        }
-        
-        translate([-8.5, 0]) {
-            long_buildings(21);
-            short_buildings(21);
-        }
-    }
-
-    module tile10() {
-        rotate(90)
-        tile05();
-    }
-
-    module tile15() {
-        module tile() {
-            tileW = 30;
-            roadW = 25 / 3;
-            roadL = tileW * 0.75;
-            halfRW = roadW / 2;
-            halfTW = tileW / 2;
-            
-            module road() {
-                translate([halfTW, halfTW, halfTW * 0.5 + 4.75]) {
-                    linear_extrude(2)
-                        arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
-                        
-                    linear_extrude(3)
-                        difference() {
-                            arc(radius = halfTW, angle = [180, 270], width = roadW, $fn = 64);
-                            arc(radius = halfTW, angle = [180, 270], width = roadW - 2, $fn = 64);
-                        }
-                }				
-            }
-            
-            base();
-			color("LightYellow")
-            road();	
-            translate([1, 0, 0])
-                pillar();	
-            translate([0, 1, 0])
-            rotate(-90)
-                pillar();
-                
-            translate([8.5, 8.5]) 
-                short_buildings(12);
-                
-            translate([8.5, -8.5]) 
-                short_buildings(12);
-        }
-
-        rotate([0, 90][round(rand(0, 1))]) {
-            tile();
-            rotate(180)
-                tile();
-        }
-    }
-
-    module tile07() {
-        tileW = 30;
-        roadW = 25 / 3;
-        roadL = tileW * 0.75;
-        halfRW = roadW / 2;
-        halfTW = tileW / 2;
-        
-        module road() {
-            module road_shape() {
-                translate([halfTW, halfTW]) 
-                    arc(radius = halfTW, angle = [135, 295], width = roadW, $fn = 64);
-                mirror([0, 1, 0])
-                translate([halfTW, halfTW]) 
-                    arc(radius = halfTW, angle = [135, 295], width = roadW, $fn = 64);
-            }
-            
-            translate([0, 0, halfTW * 0.5 + 4.75]) {
-                linear_extrude(2)
-                intersection() {
-                    square(tileW, center = true);
-                    road_shape();
-                }
-                
-                linear_extrude(3)
-                intersection() {
-                    square(tileW, center = true);
-                    difference() {
-                        road_shape();
-                        offset(-1) 
-                            road_shape();
-                    }
-                }
-            }
-        }
-        
-        base();
-		color("LightYellow")
-        road();	
-
-        translate([1, 0, 0])
-            pillar();	
-        translate([0, 1, 0])
-        rotate(-90)
-            pillar();
-        mirror([0, 1, 0])
-        translate([0, 1, 0])
-            pillar();
-            
-        translate([-8.5, 0]) {
-            long_buildings(21);
-            short_buildings(21);
-        }
-        
-        translate([8.5, 8.5]) 
-            short_buildings(12);
-
-        translate([8.5, -8.5]) 
-            short_buildings(12);
-    }
-
-    module tile11() {
-        rotate(90)
-            tile07();
-    }
-
-    module tile13() {
-        rotate(180)
-            tile07();
-    }
-
-    module tile14() {
-        rotate(-90)
-            tile07();
+            city_tile(i);
     }
 }
\ No newline at end of file