This web content delves into the world of recreational math, starting with a simple drawing challenge and delving into complex mathematical concepts using the example of the seven bridges of Königsberg. The author explores the idea that every vertex must have an even number of lines for a drawing to be possible without retracing. The piece also discusses the concept of two-coloring doodles, turning doodles into networks, and the difficulty of solving problems like finding a Hamilton cycle or three-coloring a network. The P vs NP problem, one of the Millennium Prize Problems, is highlighted as an ongoing challenge in mathematics.
https://chalkdustmagazine.com/features/the-doodle-theorem-and-beyond/