From 4416a1276f1591b27acf20a8dd0e4573a8dbee6d Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Wed, 15 Apr 2020 14:01:22 +0800
Subject: [PATCH] add fern_leaf

---
 examples/lsystem3_collection.scad | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/examples/lsystem3_collection.scad b/examples/lsystem3_collection.scad
index 42b9fe2e..b968c71a 100644
--- a/examples/lsystem3_collection.scad
+++ b/examples/lsystem3_collection.scad
@@ -1,7 +1,7 @@
 use <experimental/lsystem3.scad>;
 use <hull_polyline3d.scad>;
 
-for(line = tree()) {
+for(line = fern_leaf()) {
     hull_polyline3d(
         [line[0], line[1]], 
         thickness = 0.25, 
@@ -28,4 +28,15 @@ function hilbert_curve(n = 3, angle = 90, leng = 1, heading = 0, start = [0, 0,
             ["D", "|CFB-F+B|FA&F∧A&&FB-F+B|FC//"]
         ]
     )
-    lsystem3(axiom, rules, n, angle, leng, heading, start);  
\ No newline at end of file
+    lsystem3(axiom, rules, n, angle, leng, heading, start);  
+
+function fern_leaf(n = 8, angle = 4, leng = 1, heading = 0, start = [0, 0, 0]) = 
+    let(
+        axiom = "EEEA",
+        rules = [
+            ["A", "[++++++++++++++EC]B^+B[--------------ED]B+BA"],
+            ["C", "[---------EE][+++++++++EE]B&&+C"],
+            ["D", "[---------EE][+++++++++EE]B&&-D"]
+        ]
+    )
+    lsystem3(axiom, rules, n, angle, leng, heading, start, forward_chars = "ABCDE");  
\ No newline at end of file