From c9027dfa2f903a9f041d4e2105bfee3a946617df Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Wed, 15 Apr 2020 10:01:35 +0800
Subject: [PATCH] add sierpinski_carpet

---
 examples/lsystem_collection.scad | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/examples/lsystem_collection.scad b/examples/lsystem_collection.scad
index ac7c0473..a733b922 100644
--- a/examples/lsystem_collection.scad
+++ b/examples/lsystem_collection.scad
@@ -1,7 +1,7 @@
 use <experimental/lsystem2.scad>;
 use <line2d.scad>;
 
-for(line = island_curve()) {
+for(line = sierpinski_carpet()) {
     line2d(
         line[0],
         line[1],
@@ -211,6 +211,16 @@ function sierpinski_square(n = 8, angle = 45, leng = 1, heading = 0, start = [0,
         ]
     )
     lsystem2(axiom, rules, n, angle, leng, heading, start);      
+
+function sierpinski_carpet(n = 4, angle = 90, leng = 1, heading = 0, start = [0, 0]) = 
+    let(
+        axiom = "F",
+        rules = [
+            ["F", "F+F-F-F-G+F+F+F-F"],
+            ["G", "GGG"]
+        ]
+    )
+    lsystem2(axiom, rules, n, angle, leng, heading, start, forward_chars = "G");          
     
 function terdragon(n = 5, angle = 120, leng = 1, heading = 0, start = [0, 0]) = 
     let(