Proclus, writing of geometry, said: "I emulate the Pythagoreans who even had a conventional phrase to express what I mean "a figure and a platform, not a figure and a sixpence," by which they implied that the geometry which is deserving of study is that which, at each new theorem, sets up a platform to ascend by, and lifts the soul on high instead of allowing it to go down among the sensible objects and so become subservient to the common needs of this mortal life (O'Connor, J, & Robertson)."

Play with the concepts of the Pythagorean Theorem here.

View an interactive proof of the theorem here.