On Sat, Nov 16, 2013 at 09:47:02AM -0800, Christopher Smith wrote:
>    In sympy/geometry/polygon.py:
> 
>  > @@ -446,7 +446,7 @@ def _isright(a, b, c):
>  >              ba = b - a
>  >              ca = c - a
>  >              t_area = simplify(ba.x*ca.y - ca.x*ba.y)
>  > -            return bool(t_area <= 0)
>  > +            return bool(t_area.is_negative)
> 
>    So just to be clear - the proposed behavior of wrapping a True, False or
>    None in bool is a change that is being made by this PR.

Not by this pr.  But I think, I got your idea.