Steps: 7 steps; Formula quantity: 2-493; Average reduction step: about 48.
The seven-step reduction method of the third-order Rubik's Cube Petrus method has the following reduction ideas:
1. Turn the yellow center block up, turn the white edge block to the top, and let the four white edge blocks and the yellow center block form a small flower.
2. Align the side blocks adjacent to the top white edge block with the center block of the same color, and rotate180 to make the white edge block flush with the bottom white center block, so that the four white edge blocks and the white center block form a cross.
3. The white corner is on the third floor: turn the Rubik's cube to put the white corner on the right hand side, and do the right hand formula 1~5 times until it turns to the white background; White corner is on the first floor: first put the white corner on the right hand side to make the right hand formula and transfer it to the first floor, and then follow the above steps.
4. Make the word "T" bigger: the third layer edge block without yellow is aligned with the center block with the same color on the side. Rotate the third layer away from the top edge. A "point" on the top: press+right hand formula twice+push. See the picture for details.
5. No small fish: put the yellow corner block in front and make the right small fish formula in the upper left corner. The specific steps are shown in the figure.
6, no eyes: make an eye formula to restore a pair of eyes, see the picture for specific steps.
7. There is no complete surface: left fish+right fish or right fish+left fish restores a complete surface. See the figure below for specific steps.
Brief introduction of the third-order Rubik's cube
Rubik's cube is called Rubik's cube in Taiwan Province Province of China, twisted dice in China Hong Kong Special Administrative Region, and Rubik's cube and Rubik's cube abroad. Ern Rubik, a Hungarian architecture professor and sculptor, invented a mechanical educational toy in 1974, formerly known as Rubik's cube. 1980, Ideal Toys sold this toy and renamed it Rubik's Cube.
The Rubik's Cube was the most popular in the 1980 s, and it did not decline. By the end of June, 2009, 5438+ 10, the global sales of Rubik's Cube had exceeded 350 million pieces.