"How do you split a rectangle into thirds?"
"Well, you could cut from the center of the rectangle to the middle of one of the long sides, then from the center out at an angle that isn't really 120˚ from the previous cut..."
"What would that angle be?"
"Um... You could cut it in half and redefine equal."
"Or, cut it into quarters, we each take a piece, and wrestle for the last one."
"Let's go with that."