The fourth-order Rubik's Cube formulas include: edge-joining formula, in-situ edge-turning formula, opposite-edge-changing formula, and single-edge turning formula. The details are as follows:
1. The edge-making formula: Uw' (R U R' F R' F' R)? Uw
2. The edge-turning formula in place: R U R' F R' F' R?
3. Dual-edge transposition formula (P special formula) Uw2 ( MR2 U2 )2 MR2 Uw2
4. Single-edge transposition formula (O special formula) Rw U2 CR ( Rw U2)2 Rw' U2
Extended information
The inventor of the Rubik's Cube is ERNO RUBIK of Hungary.
Born on July 13, 1944 in Budapest, Hungary, his father was an engineer at the Budapest ESZTERGOM aircraft factory and was engaged in glider design. He graduated from Budapest University of Technology in Architecture in 1967 and then studied sculpture and interior design as a postgraduate student. He worked as an architect from 1971 to 1975, and then became a professor at the Budapest Academy of Applied Arts.
He likes to play with geometric cardboard and wooden models in his room. In the spring of 1974, he took some wooden blocks, put them together with retractable springs, and started twisting them. During the twisting process, he was fascinated by seeing the positions of the small cubes changing with each other.
Then, he pasted the same colored paper on 9 small squares on each side, using 6 colored papers on each of the 6 sides, and twisted it again. He liked the change of different color patterns, but then found that he could not turn it around. He spent a whole month doing mathematical calculations and finding ideas for color restoration.
Drucker submitted a patent application to the Hungarian Patent Office on January 30, 1975 for the cube toy, and the patent was granted on December 31, 1977. The patent number is 170062. Since then, the Rubik's Cube has become popular all over the world and is regarded as the pride of Hungarians and a representative of national intellectual creation. The inventor Erno Rubik is an idol of the Hungarians.
Reference material: People's Daily Online - Patented Rubik's Cube that affects the world
Reference material: Baidu Encyclopedia - Fourth-order Rubik's Cube