It isn't, its a constraint solver, a closer analogue would be sudoku solving. The name arises because you start by population all grid squares with all possibl

It isn't, its a constraint solver, a closer analogue would be sudoku solving. The name arises because you start by population all grid squares with all possible tiles, and use the constraints to progressively eliminate tiles until there is only one for each grid square. Sometimes you need to make a random choice between equally valid tiles, so in a sense you start with a superposition of possible tilings, and reduce to a single one, hence the name.