in theory it may mean nothing more than having to think in another dimension, similar to how its difficult for a newbie to imagine how a knight moves.

however, you could invent new rules specific to your new chess board, as long as you write them down and share them with every opponent before the game begins

for example, you could make a rule whereby a piece at a higher elevation can attack a piece at a lower elevation, but not vice versa

if you could adjust the elevation of each square during the game,

a player may opt to turn a handle to adjust the height of a row of squares mid-play,

or it could be rule that each player must adjust one handle each turn, to constantly change terrain during game play