[twister881]

Perpetual motion machine:

Strap a piece of buttered toast to a cat's back and drop from a 5-story building.

[Bob]

Perpetual motion machine:

Strap a piece of buttered toast to a cat's back and drop from a 5-story building.

Making that scheme work requires an expensive carpet underneath to attract the buttered toast. Dropping the cat from shoulder height should be sufficient. :=)