You can freely build on How the 2x2x2 Magnetic Puzzle Cube Works
This patent expired in 1990. Every claim — 0 independent, 1 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Moleculon Research Corp
Patent granted
1972
Expired
1990
Forward citations
75
What this patent covers
The patent describes a puzzle made of eight cube-shaped pieces that form a larger composite cube. Each piece has magnets on its hidden faces to keep the structure together while allowing specific groups of four cubes to rotate around three perpendicular axes. By rotating these groups, a user can scramble the colors on the outer faces and then attempt to restore the original pattern. The mechanism relies on the ability to move sets of four pieces independently without the entire cube falling apart.
What is now free to use
All 1 claims of US 3655201 are in the public domain. Specifically:
The 1 dependent claim add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover 3x3x3 puzzle cubes (like the Rubik's Cube) which use a central internal mechanism rather than magnets on cube faces.
Does not cover puzzles that use mechanical interlocking tracks or internal stems instead of magnetic attraction to hold pieces together.
Does not cover non-cube geometries that do not allow for the rotation of sets of four pieces around three perpendicular axes.
Who is building on this today
Modern puzzle manufacturers continue to refine the 2x2x2 cube design, often incorporating internal magnets to improve rotation feel and alignment. Companies like MoYu and GAN produce high-performance versions of this specific geometry for competitive speedcubing.
Products built on expired version of this technology
Magnetic 2x2x2 puzzle cubes
Early prototypes of group-rotation puzzles
How to cite this patent in your documentation
Moleculon Research Corp. US Patent 3655201. Pattern forming puzzle and method with pieces rotatable in groups. Granted 1972, expired 1990. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.