The One with the Brain Teaser

In Colorado we played a game of Cranium Wow. The teams were boys versus girls, except Nick was on the girl's team :) Anyways, one of the questions the boys got was: True or False, you can cut a cake into 8 pieces with three straight cuts.

They guessed false after quickly trying to dissect a cake in their heads.

The answer is true.

And we were baffled.

We spent 10 minutes trying to figure it out. I even almost called my dad as a sort of "lifeline." Here are our attempts at trying to cut a cake into 8 pieces with three cuts:
It didn't matter if the cake was round or square. It didn't matter where the lines crossed. The most we could ever get was 7 pieces!

Finally Andy went upstairs and googled the question. You can cut a cake into eight pieces by cutting down through it in an "x" and then cutting through the middle of the cake.

Tricky tricky.