Patch #1513695:  New turtle module, with demos.
diff --git a/Misc/ACKS b/Misc/ACKS
index 5999163..e3a3d9f 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -412,6 +412,7 @@
 Bjorn Lindqvist
 Per Lindqvist
 Eric Lindvall
+Gregor Lingl
 Nick Lockwood
 Stephanie Lockwood
 Anne Lord