http://www.bakersroyale.com/cakes/baking-basics-the-easy-way-to-cut-even-cake-layers/

OMG!  I have...like...15 of those down in my basement next to all my unfinished needlework projects!  What a great idea!  I can't cut a cake evenly to save my life.  Thanks for the link! 

Now if only they made square embroidery hoops...

Well how simple is that.

They apparently do make square ones... but they have rounded corners and are actually expensive compared to the round ones... also, not in as many sizes...

http://www.joann.com/edmunds-wood-embroidery-hoop-6-/xprd1144648/

http://www.joann.com/q-snap-quilting-frames-size-11-x11-/prd2868/