A inquisitive dog approached a group of four tires that were spread out on the ground and worked out how to pick them up all at once. When the dog discovered the tires were different sizes, he rationally stacked the smaller ones inside the larger ones, then inserted his nose within the pile and picked it up.
The clever dog assists his owner in moving tires and even discovers out how to carry four tires in one bite.
via Boing Boing