I took Billy's joke from a small limerick I wrote in sixth grade. It went like this:
My brother picked rocks from a clump.
They soared in the stream with a 'plump!'
"I skipped one!" he cried,
To which I replied,
"D'you think you could get it to jump?"
Obviously, I'm a poetic master.
Also, the little dude in Billy's drawing (the weird thingy throwing the rock) was a character I invented in fifth grade. His name was literally "Character." I wasn't feeling creative that day, I guess.