[sxjkdspc] Stacked chess abilities

Consider a chess variant which permits more than one piece to occupy a single square, but all pieces on a given square must belong to the same side.

When there is multiple occupancy, a composite piece gets formed that has the sum of the movement abilities of the component pieces, and they can all move at once according to the summed ability.  They don't have to all move at once: the pieces can separate and move according the subset of movement of the separated piece.

This suggests starting on a large board with many weak pieces.  In the opening phase, players may maneuver collections of weak pieces on top of each other to form stronger pieces before engaging the enemy.

Instead of an infinite range piece like a bishop, we could have N ferzes stacked on top of each other yielding a bishop with limited range of N steps diagonally (or N^2 or 2^N).