Click a square size in the tray to select it. Then click a grid cell to place that square. Click a filled cell to remove it. Squares may not overlap or cover gray spaces, and you must use all the pieces to cover every white square.
Click a square size in the tray to select it. Then click a grid cell to place that square. Click a filled cell to remove it. Squares may not overlap or cover gray spaces, and you must use all the pieces to cover every white square.