Your next reading will take a dive into purely combinatorial descriptions of surfaces, i.e., those that capture connectivity, but not geometry.  These descriptions and data structures will provide the foundation for all the geometry and algorithms we'll build up in this class.  (The reading also provides the essential background for your first written and coding assignments!) The reading is Chapter 2, pages 7–20 of our course notes, which can always be accessed from the link above. As usual, you should write a short 2-3 sentence summary, plus one question about something you didn't understand or want to know more about. Handin instructions can be found in the Readings section of the main page.