In tri-dimensional chess some rule sets allow for the attack board to be moved from the peg on top of the main board to the peg on the underside (as long as the attack board is unoccupied). What is the point of this inversion? Especially since some rule sets deem it okay to ignore inversion rules.
Inversion seems redundant since the attack board's level under a board is the same as the level if it's on top of the board below. i.e. KL under neutral board is equal as KL over white's board.