Perfect Shape is a collection of pure Ruby geometric algorithms that are mostly useful for GUI manipulation like checking containment of a mouse click point in popular geometry shapes such as rectangle, square, arc (open, chord, and pie), ellipse, circle, polygon (Ray Casting Algorithm aka Even-Odd Rule), polyline, polyquad, polycubic, and paths containing lines, bezier curves, and quadratic curves. Additionally, it contains some purely mathematical algorithms like IEEEremainder (also known as IEEE-754 remainder).