LIT For every side n from 1 through 9, the number of cells with x = y = z = (n−1)/2 is 1 when n is odd and 0 when n is even. The cube of 7 therefore has one center, (3,3,3).
AMBER Calling that center the keeper is the galaxy's assigned name for the cell.
WALL A center cell is not a mind, and it is not evidence that an even cube is empty in any other sense.