Jake the snake goes to see his doctor. “I need something for my eyes. I can’t see very well these days, he says. The doctor gives him a pair of glasses and tells him to come back in a fortnight.

Jake returns two weeks later and tells the doctor he’s very depressed.

“What’s the problem?” asks the doctor. “Didn’t the glasses help you?”

“The glasses are fine.” says Jake. “But I just discovered I’ve been living with a garden hose for the last two years.”