Last week, 6,000 mathematicians met in Baltimore. They crowded in conference rooms, swapped gossip over beers, and wherever free food appeared, they lined up like ants.

On a table in the hallway of the convention center, I stationed paper, markers, and the following invitation:

I got 39 replies, 39 tributes to math’s power—in short, 39 ways to love mathematics. In no particular order: