(quoted from The Legend of Howard Thrush)
When he first went into grad school, it looked like it was going to be quite the golden age for people like him. Mathematics was, rightfully, becoming more and more important in the world. People were hiring mathematicians to help them with everything: designing flying machines, figuring out travel plans for salesmen who wanted to visit a bunch of towns once each, working out how much to charge per yard for their carpets to maximize their profits and how much paint to buy if they needed to cover the area under the curve y= 1/x^{2} between x= 0 and x = 1.
The problem was, with so many mathematicians working on problems day and night, there just weren't enough variables to go around. It didn't take long for them to notice that with just a to z and A to Z, there was barely enough to last out the year. Talk of the Great Variable Shortage filled the mathematical mess halls and all those great brains set themselves to figuring out what to do. The ones who'd spent too much time in civil work proposed a rationing, and seeing as nobody had a better idea, they started in with that. At night, when few people were working anyway, you could use just about any variable you wanted, but during the day only people working on the most important of problems had access to the choicest of them like x and t.
The few mathematicians with a good liberal training in the classics made an important contribution by suggesting the use of foreign substitutes like Θ and ℵ, but everyone knew that this was just delaying the inevitable. And nobody liked to think what would happen then.
