A 44-second video is getting people asking a simple but maddening question: will they ever meet? The clip shows two men walking around a massive plastic-wrapped cylindrical water tank in a gravel yard. Both are walking in the same direction, with one trailing the other, so every time it looks like they might finally cross paths, the gap between them is still there. Throughout the video they keep missing each other, and viewers can't stop watching to see whether anything changes.

The clip is a real-life demonstration of relative circular motion. When two people walk at the same pace in the same direction around a circle, the distance between them stays the same, much like two runners holding equal speed on a track. They would only meet if one of them reversed direction, sped up, slowed down, or if the two coordinated their movements. The size of the tank likely adds to the puzzle, since a wide cylinder can make it hard to see where the other person is. It looks like a joke, but it shows how pacing and direction decide whether two moving people ever meet.