Once upon a time there were two identical twins

Once upon a time there were two (as opposed to three) identical twins, who, in defiance of all we know about the genetic basis of intelligence, were anything but identical mentally. One of them was, quite frankly, stupid, while the other was very sharp indeed. In fact, he was a master of ready wit and stunning repartee.

One evening the stupid twin went to a circus that happened to be in town. He went early so he could get a good seat in the front row, right beside the ring, and he thoroughly enjoyed the experience. He marvelled at the elephants, cowered from the lions, and gaped at the trapeze artists in their skimpy costumes; he reacted exactly the way he was meant to.

Last of all, on came the clowns. They were his favourite bit of the circus. All that falling over, all that water, all those custard pies - it was hilarious. The lead clown was the most ludicrous of the lot: he had bigger shoes, baggier trousers, brighter make-up and the most enormous red nose. And part of the lead clown's job was to make fun of people in the audience.

So the clown looked around for someone to hassle, and saw a rather stupid-looking man sitting right in the front row. Ideal. He went up to the stupid twin and said:

"Sir, are you the front end of an ass?"

The stupid man sat there wishing that he hadn't come, wishing that the clown would go away and pick on someone else. He knew he wasn't very intelligent, and he knew he would come out of this looking very foolish. But he spoke up. "No," he said.

"Sir, are you the back end of an ass?" the clown continued.

"No, I'm not," the stupid man replied.

"Then, sir," the clown said slowly, letting the audience savour the moment, "you are no end of an ass!"

The audience, having a fairly poor sense of humour, erupted into laughter. The stupid man just wished he could die. Fortunately for him, the show was soon over.

When he got home, the stupid man told his brother what had happened.

"Don't worry," said the master of ready wit and stunning repartee, "I am a master of ready wit and stunning repartee. Tomorrow night I will go to the circus and make that clown look foolish."

So the next night, the master of ready wit and stunning repartee went to the circus, and got a front row seat. Being an intelligent man, he was considerably less impressed by the sight of dumb animals being made to do tricks, although he had to admit that the trapeze artists were rather tasty.

Then the clowns came out, and the one with the biggest shoes, baggiest trousers, brightest make-up and most ludicrously over-sized nose looked around the audience for someone to make fun of. He could not believe his luck. There, sitting in the front row, was the stupid man he'd got such a laugh out of the night before. So the clown approached the master of ready wit and stunning repartee and asked:

"Sir, are you the front end of an ass?"

"No," said the master of ready wit and stunning repartee.

"Sir, are you the back end of an ass?" the clown continued.

"No, I'm not," replied the master of ready wit and stunning repartee.

"Then, sir," said the clown, "you are no end of an ass!" The crowd went wild with laughter. The joke went down even better than it had the night before, and the clown felt on top of the world.

But just then the master of ready wit and stunning repartee stood up, smiled sadistically and said:

"Fuck off, you red-nosed bastard."