public void moveDown(Tetromino piece, int x, int y, int orientation) {
		boolean[][] tiles = piece.getTiles();
		int count = 0;
		// clear the current piece out
		int width = piece.getTiles()[0].length == 9 ? 3 : 4; // get width (3 or 4) of piece
		width = piece.getTiles()[0].length == 4 ? 2 : width;	

		for(int row = 0; row < width; ++row) {
			for(int col = 0; col < width; ++col){
				if(tiles[orientation][count++] && !screen[row+y][col+x].isEmpty()){
					screen[row+y][col+x] = new Square();
				}
			}
		}
		addPiece(piece, x, ++y, orientation);
	}