Damped Lissajous Curves ♦
If two perpendicular pendulums are used to control the movement of a pen, the curve traced out is a so called damped Lissajous curve.
2013 
malin christersson
2013
malin christersson
If two perpendicular pendulums are used to control the movement of a pen, the curve traced out is a so called damped Lissajous curve.
Imagine three coloured regions bordering to each other such that all three regions have exactly the same border!
The human brain uses shadows to interpret how objects move. By faking the shadow, one can fake the perceived motion of an object.