In the transition from mathematical billiards to physical billiards, where a ball goes from being a point particle to having a positive radius, it may seem intuitive to assume that no categorical difference exists between the two. A new proof-of-concept paper by **Leonid Bunimovich** says otherwise. Bunimovich discovered as the radius of a physical billiard ball increases, the change in the behavior of the entire system is equivalent to modeling mathematical billiards with a smaller table. With increasing radius, the geometry of the system evolves. For instance, some parts of the table may become inaccessible to the ball. This results in a progression in the dynamics of the system between mathematical and physical cases, and it may become more or less chaotic with changing radius.