Here are some puzzles that people can answer while waiting for the course to officially start. I will call my exercises "puzzles" to distinguish them from the exercises in the book, and number them so we can keep track of them.

**Puzzle 1.** What is a "poset" according to Chapter 1 of Fong and Spivak's book?

**Puzzle 2.** How does their definition differ from the usual definition found in, e.g., Wikipedia or the nLab?

**Puzzle 3.** What do mathematicians _usually_ call the thing that Fong and Spivak call a poset?

I think I want to use the usual mathematical term: I don't want to release 70 students into the world who use a nonstandard definition of "poset".

**Puzzle 4.** List some interesting and important examples of posets that haven't already been listed in other comments in this thread.