Thirteen, Thirteen, Thirteen!

A young man was strolling down a street in south London. As he passed
a large building with a fence around it, he heard a group of people chanting
"Thirteen, thirteen, thirteen, thirteen" over and over again.
Curious, he tried to see over the fence, but couldn't. Then he spotted
a knot in the wood, and put his eye to the hole. He just managed to spy
some old people sitting in deckchairs chanting, before a finger came
out of nowhere and poked him in the eye. As he staggered back, the old
people started chanting, "Fourteen, fourteen, fourteen,
fourteen..."