Category talk:Patterns with D4 symmetry

I think that there are two separate types of D4 symentry when applied to a square grid.

1. The rotation point can be centered on a vertex or the point between four cells. The pond is an example.
2. The rotation point can be centered on a cell. The traffic light is an example.

Perhaps two separate categories would be appropriate.--Scot Ellison 07:59, 6 July 2011 (CDT)