Turning a coin on itself is a trivial gesture. But when you see that a can move and vibrate for several minutes, it’s easy to think that there’s something interesting to study behind this movement. And that’s what we did. But taking measurements, when the movement of the coin seems so complex, required us to set up experiments that we had to correct and improve in the course of our study to arrive at reliable, usable measurements. These measurements have enabled us to learn a great deal about the coin’s rotations, and to make variables that describe the movement of the coin.