//a,b at 45 from eachother, or 90
public static bool LeftOf(this Direction a, Direction b)
{
if (a.Ortho() && b.Ortho())
{
return(a.RotClockwise90() == b);
}
else
{
return(DirectionUtil.ContinueRot(a, b) == a.RotClockwise90());
}
}
