Today I have a short one, a follow-up to the post on pizza sizes. Recently, I was in my local pizza place where I had to choose between 32 and 46cm pizza. The bigger one cost 5 PLN more. Even without looking at my table, I chose the bigger one. I knew, however, that I’m going to eat only half of my pizza so I asked to pack the remaining half.

During my studies, I spent one semester at KU Leuven. There is one interesting mathematical problem from those times I’d like to share. This Belgian city has a topology of a big circle with a city inside. One early, cold, damp, and windy morning (as it is in Belgium) when I was coming back from some trip I had to go from the railway station (right side of the ring) to my dormitory (bottom of the ring).

One morning I was standing in a queue in my local bakery, and I’ve seen a woman buying one of those small quasi-pizzas. Pizzas ~20cm in diameter. Immediately I thought about how profitable it is when compared to the full-size 42cm pizza. Since the area of a larger pizza is 4 times bigger, of course, it’s not worth buying smaller pizzas. Then I thought about fitting smaller pizzas inside the bigger one.