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Flat Cube puzzle shown to require at least 27 moves to solve worst-case scramble

A mathematical analysis of a 2D Rubik's Cube-like puzzle called the Flat Cube establishes a lower bound of 27 for God's number, the maximum moves needed to solve the most adversarial scramble, by mapping lozenge tilings to 3D cube arrangements.

WHY IT MATTERS

This is a recreational mathematics result with no direct engineering consequence, carried by a single source with no corroboration. The technique of mapping a 2D tiling problem to a 3D packing problem is a notable combinatorial argument, but the practical relevance for software builders is minimal.

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The three things worth knowing

01

The Flat Cube is a 2D puzzle of rhombus-shaped lozenges where three lozenges forming a hexagon can be twisted together by multiples of 60 degrees.

02

God's number for the Flat Cube is shown to be at least 27, compared to 20 for the standard Rubik's Cube when a 180-degree twist counts as one move.

03

The proof maps each lozenge tiling to a configuration of unit cubes in a 3-by-3-by-3 tray, where each twist adds or removes exactly one cube, so an empty-to-full transition requires 27 moves.

THE CLUSTER

Same story, 2 feeds.

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mathenchant.wordpress.com via Hacker News Solving the Flat Cube Open ↗
mathenchant.wordpress.com via Lobsters Solving the Flat Cube Open ↗