Professor Puzzle: Einstein's Atom Puzzle

Take the atom apart. Then discover that putting it back is the actual puzzle.

Part of Professor Puzzle's range of metal brainteasers — disentanglement puzzles themed on historical figures and curiosities. The object is always the same: take it apart, then put it back together, which is the half nobody warns you about.

Small enough for a desk or a stocking, hard enough to sit there unsolved for a fortnight. Comes with solution instructions, for when pride finally loses.

Perfect for: desk fidgeters, Secret Santa, people who say they're good at puzzles, and gifts for someone who is impossible to buy for.