Steiner's Porism
Construct an animation illustrating Steiner's Porism: For any two (nonconcentric) circles one inside another, if circles are drawn successively touching them and one another so the last one touches the first, then it will always happen whatever the position of the first circle. 
Investigate the various properties in the Steiner's Porism. 

Explore the following properties of regular polygons: 
Construct Steiner's porism in which the polygons formed by the centers of the rotating circles share the same properties as in the above problem 