On the Subject of XO-Rays
Two symbols are revealed in the window by an x-ray scanner, which shows a thin section of each symbol at a time. Both symbols are scanned simultaneously. When both are scanned, they will appear the same as neither being scanned.
The scan progresses in a random direction (up, down, left, or right) for each symbol independently. The scanning directions will change on each repetition.
Both symbols have been assigned three numbers. Push the buttons with number assigned to exactly one (i.e. not both) of the symbols in either order.
1 2 3
1 2 4
1 2 5
1 3 4
1 3 5
1 4 5
2 3 4
2 3 5
2 4 5
3 4 5