Yuri

I was at Microsoft Research in Redmond this week.  I met a Russian logician named Yuri Gurevich who told me a funny story about a math class when he was a child:

I remember, in a geometry class, my teacher wanted to prove the congruence of two triangles. Let’s take a third triangle, she said, and I asked where do triangles come from. I worried that there may be no more triangles there. Those were hard times in Russia, and we were accustomed to shortages.

He was afraid they might have run out of triangles!