An impossible shape made conveniently portable. FanXin's mini Penrose trihedron distils the famous geometry into a three-centimetre keychain puzzle - turning pieces around its triangular axes while looking like a mathematical paradox that gave up hiding.

Genuinely functional twisty mechanics hide beneath the novelty: corner-style turns cycle pieces exactly as the full-size version does. Bright stickerless colours keep the impossible object cheerful rather than eerie.

For mathematicians, magpies, and anyone whose keys deserve better conversation pieces.

Features:

• Miniature Penrose triangle puzzle
• Working twisty mechanism
• Vivid stickerless finish
• Pocket-sized collector piece