<Mission>
To get the number of possible Tetris cube patterns
<Tetris pieces & colors>
- J piece Blue
- L piece Orange
- S piece Green
- Z piece Red
- T piece Magenta
- O piece Yellow
<Other pieces>
- Center piece Black
- Edge piece White
<Conditions>
- 6 Tetris pieces (+ Black center & White edge) appear once
- Colors of Tetris and other pieces do not change
- Center colors are Orange, Green, Red, Magenta, Yellow, and Black (neither Blue or White)
- Positions of the Center colors are not pre-established
<Method>
- Brute force
- Place the Blue J piece on the back of the U side of the cube, and then place the Tetris colors 2 to 6 on the U→F→R→B→L→D sides in that order.
<Result>
It was found that there are 19 patterns, as shown in the simulation below.
<Observation>
The number of corners that a Tetris piece occupies is as follows:
- S, Z, O pieces: 1 corner
- T piece: 0 or 2 corners
- L, J pieces: 1 or 2 corners
They can contain a minimum of 5 corners (1+1+1+0+1+1 = 5) and a maximum of 9 corners (1+1+1+2+2+2 = 9). Because the cube has 8 corners, it is necessary to arrange the T, L and J pieces so that T contains 2 corners, L and J contains 1 corner and 2 corners (1+1+1+2+1+2 = 8).
In this mission, the conditions require that the Blue J piece must have 2 corners and the Orange L piece must have 1 corner, but if we change the conditions and allow the Blue to be the center color, we can make the former have 1 corner and the latter have 2 corners (since both pieces are symmetrical), which would add 19 new possible patterns.