A fireman is polishing his fire engine outside the fire station when he notices a young girl coming down the street in a little red cart with little ladders hung on the side and a garden hose tightly coiled in the middle. She is wearing a fireman’s helmet and has the cart tied to both a dog and a cat.

Playing the part, the fireman walks over to take a closer look.

“That’s a lovely fire engine,” he says admiringly.

“Thank you sir,” replies the little girl.

The fireman takes a closer look and happens to notice that the little girl has tied one of the cart’s strings to the dog’s collar and the other to the cat’s testicles.

“Little colleague,” says the fireman, “I don’t want to tell you how to run your fire engine, but if you were to tie that rope around the cat’s collar, I think you could probably go a lot faster.”

The little girl pauses for a moment, looks at the wagon, at the dog and at the cat, then shyly looks into the fireman’s eyes and says, “You’re probably right, but then I wouldn’t have a siren, now would I?”