debugger22/sympy — pull request #10 by smichr (2014-08-19 17:43:53+00:00)
Title: raise error for non-pi ellipse rotation

I think this should safeguard the evolute method. Also, non-pi rotations are not allowed as these would give rise to a "ferris wheel" rotation which is different than all other rotations. It seems better to just raise NotImplemented.