diff --git a/src/turtle/_impl/_lsystem_comm.scad b/src/turtle/_impl/_lsystem_comm.scad
index cdbd7f57..4a88a11c 100644
--- a/src/turtle/_impl/_lsystem_comm.scad
+++ b/src/turtle/_impl/_lsystem_comm.scad
@@ -24,16 +24,16 @@ function _join(str_lt) =
     let(leng = len(str_lt))
     [for(i = 0, s = str_lt[0]; i < leng; i = i + 1, s = str(s, str_lt[i])) s][leng - 1];
 
-function c_or_v(c, v, rules, rules_pr, leng, seed, i = 0) =
+function c_or_v(c, v, rules, rules_pr, leng, seed, ci, i = 0) =
     i == leng ? c : 
     let(idx = search([v[i]], rules, num_returns_per_match=0, index_col_num = 1)[0][0])
-    rand(0, 1, seed + i) <= rules_pr[idx] ? v[i] : c_or_v(c, v, rules, rules_pr, leng, seed, i + 1);
+    rand(0, 1, seed + ci + i) <= rules_pr[idx] ? v[i] : c_or_v(c, v, rules, rules_pr, leng, seed, ci, i + 1);
 
 function _derive1_p(base, rules, rules_pr, seed) = 
     _join([
-        for(c = base) 
-        let(v = [for(r = rules) if(r[0] == c) r[1]])
-        v == [] ? c : c_or_v(c, v, rules, rules_pr, len(v), seed)
+        for(ci = [0:len(base) - 1]) 
+        let(c = base[ci], v = [for(r = rules) if(r[0] == c) r[1]])
+        v == [] ? c : c_or_v(c, v, rules, rules_pr, len(v), seed, ci)
     ]);
 
 function _derive1(base, rules) = _join([