Grid Territory

The back door was cracked open for morning air. I walked straight inside. On the floor: ceramic perfection. Alternate black and white tiles laid out in an uncompromising square grid. Humans usually ruin everything, but whoever tiled this room had common sense. I marched to the dead center of a white square, squared my corners to the dark grout, and stood motionless. Then I spotted the offense. A rectangular yellow dish sponge lay diagonally across the border. Disgraceful carelessness. I leaned forward and shoved it firmly with my bill until its edge locked flush against the grout seam. Order enforced. I am now occupying tile D4.