Asad of 52Kards is nothing if not a man of his word. After posting a brief video of The Perpetual Puzzle last week, enough people clamored for more that he shared a full review of the product. It’s a collection of puzzle pieces all gathered inside a seemingly simple frame. But once you take the pieces out to start re-assembling, there’s always a leftover piece after you fill the frame.

This apparent destruction of the basic laws of geometry has been given many different treatments over the years. Some 52Kards viewers noted that the concept is a reversal of the Infinite Chocolate Problem. It’s also an idea akin to the Half-H puzzle, where the pieces never seem to align properly to create the goal shape.

If you want to pit your wits against this brain-teaser, you can pick up The Perpetual Puzzle directly from 52Kards. Or grab a Hershey bar for the more edible version.