Believe it or not, these four squares move at the same constant speed

These four squares appear to move at different speeds, stopping and moving, waiting for each other in pairs. In reality, they are always moving at exactly the same constant speed. Seriously. I opened the GIF in Photoshop and used guides to measure it—in every frame, the squares align perfectly. »4/07/14 8:41pm4/07/14 8:41pm