The Rubik's Cube in the usual sense refers to the third-order Rubik's Cube in a narrow sense. The shape of the third-order Rubik's Cube is usually a cube, made of flexible hard plastic. First you need to center the cube, choose a color you like among the 6 colors, and then position and orient the 4 edge squares on the plane of the central square with this color, that is, the top edge. The purpose is to locate and orient the squares belonging to the 4 edge positions of the top plane. The 4 top edge squares are all placed and oriented one by one.