Folding a rectangle
Shawn Cornally posted some neat wonderings in the context of thinking about abstraction. http://shawncornally.com/wordpress/?p=3941
"This question goes like this: If I take a rectangular napkin and fold it so that the diagonally opposite corners touch, what’s the area of the new modern-arty shape? Second, why do I like the shape? (but that may be for another time)"