There are some F = front faces in front.

B = behind the back.

R = right face to right

L = left face to left

U = face up

D = face down

Take the marks in the above table as an example. F stands for clockwise rotation of 90, F' stands for counterclockwise rotation of 90, and R2 stands for right rotation180. In the following algorithm, you will see marks such as Fs, Fs', Ra, Ra', indicating that you move back and forth or left and right like a clip. S = slice, a.

Mark Fs Fs' Ra Ra'

Equivalent to F B' F' B R L R' L'

Other please and so on.