
When I was a kid I had a book called Bug's Bunny's Carrot Machine. The plot was pretty simple: Bug's Bunny built a carrot machine and had to find the right parts to make it produce normal, orange, carrot-shaped carrots.
One time when I was staying at my grandparents my grandma decided that I needed a haircut. I did not want a haircut and I put up a fight. So she came up with this device:
She took a coffee can and filled it with some bolts, washers, and other miscellaneous pieces of hardware. She said that she had read my book and was making her own carrot machine, but it was missing one vital ingredient that would provide the magic needed for carrot production... my hair.
Suddenly I decided a haircut was a pretty good idea. So she put me in the sink, snipped around the bowl, and we added my freshly cut locks to her "machine". To make it work, I simply had to march around the house and shake the can as hard as I could.
After what seemed to me like an eternity, I decided to take a peek under the lid to see the fruits of my labor. Nothing. Not even some of the oddly colored, square shaped carrots that Bugs had gotten from his first attempts. Could it be that my hair was not magical enough?
Grandma assured me that the construction of the device was sound and my hair was plenty magical. The machine simply needed to rest so the carrots would have time to grow. So we left the can on the kitchen counter and went to the other room (apparently it works better if you don't watch). We came back a short time later and... the machine had worked. I was so satisfied by that rust-covered, hairy carrot that I always volunteered to get a haircut when I went to Grandma's from then on.