Fold the Net Riddle: Which Cube Folds From This Net? Answer: B

The answer is cube B. Fold the net with the star on top, and the ring and the half-filled square become two sides that meet at the star's corner, with every symbol pointing the same way as on cube B.

How do you fold the net in your head?

Pick one square to be the top. The star works best because it touches three other squares. The arrow, the triangle and the half-filled square fold straight down around the star. The ring hangs below the half-filled square, so it folds round to become the fourth side, and the bar folds under to become the bottom.

That gives three pairs of opposite faces: the star and the bar, the arrow and the ring, and the triangle and the half-filled square. Two faces that are opposite can never be seen together on one cube.

Why are A, C and D wrong?

• A shows real faces, but in mirror order. Its left and right sides are swapped, as if you were looking at the cube in a mirror, and no turn of a real cube does that.
• C has the right three faces in the right places, but the triangle is turned a quarter turn. The riddle says symbols keep their direction, so C fails.
• D puts the half-filled square and the arrow exactly where they sit when the star is on top. The bar is the face opposite the star, so it cannot be on top in that position.

Why are cube riddles so tricky?

A cube looks simple, yet it can be arranged in many ways. With six colours, one per face, there are 30 different ways to paint a cube, if two cubes count as the same whenever one can be turned to match the other ^[1]. Turning, not mirroring, is what counts, which is exactly the trap in cube A.

A 2020 paper on logic puzzles calls a puzzle good when it has exactly one solution ^[2]. Here only B survives every check, so the riddle passes.

Want to try more spatial riddles?

These riddles ask you to fold, roll and turn shapes in your head.