function PuzzlePiece(board, i, dim, isEmpty) {
	this.div = document.createElement("div");
	var size = board.cellSize;
	var current = i;
	if (!isEmpty) {
		this.div.innerHTML = i + 1;
	}
	this.div.style.position = 'absolute';

	this.update = function(i) {
		current = i;
		var y = Math.floor(i / dim);
		var x = i % dim;

		var pos = findPos(board.div);
		this.div.style.left = (pos.left + x * size) + "px";
		this.div.style.top = (pos.top + y * size) + "px";
	}

	this.update(i);
};