Probably this is the first Cardano's Hypocycloid mechanical model, not animation, that model makers have ever built.
This motion was described first by Nicolaus Copernicus
Consider two circles of radii R and R/2 with the smaller one rolling inside the bigger circle without slipping. Copernicus' Theorem states a surprising result that a point on the circumference of the small circle traces a straight line segment - a diameter of the big circle, to be precise.
The white balls appear to be moving as a circle rolling inside of the lager circle.But what you see is actually not true. This is an optical illusion.The true path of each ball is a straight line.
The mechanical design was made by Girolamo Cardano.
Cardano's work with hypocycloids led him to the Cardan joint or gear mechanism, in which a pair of gears with the smaller being one-half the size of the larger gear is used converting rotational motion to linear motion