Imagine a rectangular prism of any color with little studs on top with the word LEGO on each one of them. a 2 by 2 LEGO brick is about the same size as a grape.
Now step on it, but after you write your will.
they're basically little plastic brick things but the plastic they're made of is like really stiff so when you step one em it kinda digs into your skin and it hurts like hell