The second-level Rubik's Cube has 12 edges.
Introduction to the second-order Rubik's Cube: The second-order Rubik's Cube, also known as pocket Rubik's Cube, mini Rubik's Cube, small Rubik's Cube, and ice cube Rubik's Cube, has a 2×2×2 cube structure and is a mechanical educational toy created by Lu Invented by Bic Alne. It has only 8 corner blocks and no other structural blocks. Its structure is similar to that of a third-order Rubik's Cube. It can be restored using the formula for restoring a third-order Rubik's Cube.
The 8 corner blocks of the second-order Rubik's Cube have 8!/24=1680 position arrangements, and each arrangement has 1107 color directions (the color direction is conserved during twisting, 3 to the 8th power Most of the colors in this theory are impossible to appear), that is, there are 1680*1107=1859760 states after the second-order Rubik's Cube is scrambled.
The farthest recovery distance of a second-order Rubik's Cube (that is, the state that requires the most steps to recover) is 11 full rotations, or 14 ordinary rotations. This result can be calculated by a computer using a brute force exhaustive algorithm.
The earliest patent for a second-order Rubik's Cube was applied for by Professor Rubik Elner on March 29, 1983. The U.S. patent number is 4378117. We are accustomed to calling it the R-structured second-order Rubik's Cube.
Chen Senli of Taiwan's Dongxian Company applied for a second-level patent for another structure on October 27, 1998, U.S. patent number, US 5,826,871.5826871, which we are accustomed to calling It is a second-order Rubik's Cube of Dongxian structure.
There are also some second-level patents for patterns, such as Mickey heads, K-balls, etc.