I hope folks straighten out the answers to Puzzles 12 and 13. It's very easy to get mixed up between left and right in category theory, or \\(\le\\) and \\(\ge\\) in preorders.
But in fact, the answers are less important than the method of figuring out those answers. There's a lot of wisdom about adjoints to be gained from these puzzles! I'll explain it soon, but in the meantime I'd really appreciate solutions where people explain their work.
This is generally true for all my puzzles: learning category theory is a process of changing how you think, so seeing how people solve problems is more useful than seeing the answers. In category-theoretic terms, there's more to an arrow than its source and target!