Spirograph

Many of us have played drawing many curves or circular diagrams using spirograph kit.
Even i played with it, but i never knew its name. It has 2 components called ststor and rotor.It has huge history to go in detail. But there is small intro i got from Wikipedia.

Spirograph is a geometric drawing toy that produces mathematical curves of the variety technically known as hypotrochoids and epitrochoids. It was developed by Denys Fisher a British engineer and first sold in 1965. The term has also been used to describe a variety of software applications that display similar curves, and applied to the class of curves that can be produced with the drawing equipment (so in this sense it may be regarded as a synonym of hypotrochoid). The name has been a registered trademark of Hasbro, Inc since it bought the Denys Fisher company.