diff --git a/src/experimental/lsystem2_collections.scad b/src/experimental/lsystem2_collections.scad
index d9f22e1c..351ac002 100644
--- a/src/experimental/lsystem2_collections.scad
+++ b/src/experimental/lsystem2_collections.scad
@@ -153,7 +153,7 @@ function sierpinski_arrowhead(n = 6, angle = 60, leng = 1, heading = 0, start =
             ["Y", "XF-YF-X"]
         ]
     )
-    lsystem2(rule, n, angle, leng, heading, start, "FG");     
+    lsystem2(rule, n, angle, leng, heading, start);     
 
 function sierpinski_square(n = 8, angle = 45, leng = 1, heading = 0, start = [0, 0]) = 
     let(
@@ -163,7 +163,7 @@ function sierpinski_square(n = 8, angle = 45, leng = 1, heading = 0, start = [0,
             ["R", "-L+F+L-"]
         ]
     )
-    lsystem2(rule, n, angle, leng, heading, start, "FG");      
+    lsystem2(rule, n, angle, leng, heading, start);      
     
 function terdragon(n = 5, angle = 120, leng = 1, heading = 0, start = [0, 0]) = 
     let(