Tricky little math puzzle

[tagryn]

The area of a square or rectangle is equal to the length times the width.

This is a puzzle a friend sent me (its an animated GIF):


Any ideas what's going on here?

Comments

[erikred.livejournal.com]

It's a beautiful canard, and it took me a while to spot it.

[tagryn]

Thanks Erik! Nice solution.