The names of the facelet positions of the cube (letters stand for Up, Left, Front, Right, Back, and Down):
|************|
|*U1**U2**U3*|
|************|
|*U4**U5**U6*|
|************|
|*U7**U8**U9*|
|************|
************|************|************|************
*L1**L2**L3*|*F1**F2**F3*|*R1**R2**R3*|*B1**B2**B3*
************|************|************|************
*L4**L5**L6*|*F4**F5**F6*|*R4**R5**R6*|*B4**B5**B6*
************|************|************|************
*L7**L8**L9*|*F7**F8**F9*|*R7**R8**R9*|*B7**B8**B9*
************|************|************|************
|************|
|*D1**D2**D3*|
|************|
|*D4**D5**D6*|
|************|
|*D7**D8**D9*|
|************|
A cube definition string "UBL..." means that in position U1 we have the U-color, in position U2 we have the B-color, in position U3 we have the L color etc. according to the order U1, U2, U3, U4, U5, U6, U7, U8, U9, R1, R2, R3, R4, R5, R6, R7, R8, R9, F1, F2, F3, F4, F5, F6, F7, F8, F9, D1, D2, D3, D4, D5, D6, D7, D8, D9, L1, L2, L3, L4, L5, L6, L7, L8, L9, B1, B2, B3, B4, B5, B6, B7, B8, B9.
So, for example, a definition of a solved cube would be UUUUUUUUURRRRRRRRRFFFFFFFFFDDDDDDDDDLLLLLLLLLBBBBBBBBB
Solution string consists of space-separated parts, each of them represents a single move:
- A single letter by itself means to turn that face clockwise 90 degrees.
- A letter followed by an apostrophe means to turn that face counterclockwise 90 degrees.
- A letter with the number 2 after it means to turn that face 180 degrees.
e.g. R U R’ U R U2 R’ U