Did you hear the one about the blind comedian?
Blind comedian Jamie MacDonald tells BBC Ouch how he makes jokes about losing his sight and the sticky situations he finds himself in.
"I was in a supermarket buying fruit and the stall dividers were mirrors. I saw a hand reaching for the same apple as me and said sorry."
Apologising to his own hand was Jamie MacDonald's first clue that his eyesight had almost gone. The 34-year-old Glaswegian has the degenerative eye condition Retinitis Pigmentosa, which became aggressive in his mid-to-late teens. It was a hard time, he says, but doesn't like to dwell on the negative moments. He sees a funny side to it and prefers to focus on that.
By way of example, MacDonald recalls a skiing trip: "The instructor made me put on a lot of high-visibility clothing and then, rather than shouting directions like I expected him to, put reins on me and guided me with those. We skied down that mountain like a high-visibility advert for triumph over adversity."
MacDonald was not always comfortable with his disability, though. It wasn't until his early 20s, while studying law at Aberdeen, that he realised he should use a "stick" or white cane. "It was probably the best thing I ever did," he says. "Life became easier and the reactions from my friends and family, which I feared, were all amazing." Their general feeling was that it was about time, he says.
MacDonald has always been something of the "funny man". Before studying law, he read history at the University of St Andrew's. There he founded a radio station where, on air, he made prank calls. "I would call up Oxford University," he says, "and ask if I could get on to their catering course."
After university, MacDonald headed for the City, and became a corporate financier, just before the credit crunch hit. Eventually redundancy gave him the excuse he needed to follow his comedy dream.
He is now happy to carry a cane and can be seen using it as a comedy prop on stage. While waving it about in the air during his stand-up show, MacDonald recreates being attacked by a wasp in the crockery isle of a department store.
Good prop it may be, but he says he has had no formal training on how to use it correctly.
Blind people are taught to sweep from left to right in front of them, making sure they are fully protected from all sides. "I don't sweep it," he says. "I poke and spin it around. I'm pretty lethal in a crowd."
MacDonald's comedy is described as anecdotal, character-driven and, he laughs, "observational".
His routine is peppered with stories about the encounters he has as a young, single blind guy at large. Instead of beer goggles, he talks of "ear goggles", where someone's voice sounds better after alcohol.
He tells his audiences that when you are blind, people can quickly slip from helpful to patronising. "I got chased down the street once by a man making a considerable effort to stop me. When he did, it was just to tell me that my lace was undone. He asked 'Do you want me to tie it for you?' When I said no, he attempted to high-five me."
Jamie MacDonald: That Funny Blind Guy 2 - The Good, the Stag and the Ugly is at Assembly George Square Studios until 25 August 2014 as part of the Edinburgh Fringe.