Jumping spider walks into a bar.
The barman says, "I'm afraid we don't serve jumping spiders".
The jumping spider says, "What about this one?" - and points to a different jumping spider.
The barman says, "I see what you are going for here. If I say yes then I have to serve this second spider. If I say no then you can make the same joke again, and again, and again, and again ad infinitum."
"Checkmate" says the jumping spider, proudly.