diff --git a/.hgtags b/.hgtags
--- a/.hgtags
+++ b/.hgtags
@@ -1,3 +1,4 @@
 79f94eaa3b9ef0ddd6c87c31ff602588c97ab86f v1.0
 c0082ca197fb5a8762017dcf21762091fd9a99cb empty model
 854077b2d7cc749acc124541ed5a6163dd07d088 growing cell
+df8602459ab009cd967403f00f7aa13cecf368b8 divide over principal axis