M×N-Dimensional Brainfuck

M×N-Dimensional Brainfuck is a brainfuck derivative with an M-dimensional tape and an N-dimensional program.

The initial pointer direction is positive in the first dimension.

The initial program counter direction is positive in the first dimension.

Instructions
Rotating from moving positively/negatively in the nth dimension results in moving positively/negatively in the (n+1)th dimension. Rotating from moving positively/negatively in the Mth/Nth dimension results in moving negatively/positively in the first dimension.