Reading: Exploring Discrete Geometry by Thomas Q. Sibley
Discrete geometry, like all of mathematics, has developed piecemeal. It is still new enough to have unsolved problems that seem just a few steps from introductory ones. The problems of [Chapter 1] seek to whet your appetite. Think about them—draw pictures for small cases, look for patterns, make conjectures, and try to solve them. Complete answers are great, but so are partial answers, guesses, and even mistakes. Recall: mathematics is not a spectator sport; so enjoy engaging with these problems. We’ll revisit these problems in later chapters, providing answers, relevant mathematics, and especially new questions probing these areas more deeply.