I was going through your stuff [2] today and developed a much better intuition for the universal property and initial/final-ness than I had previously (from the

I was going through your stuff [2] today and developed a much better intuition for the universal property and initial/final-ness than I had previously (from the beginning of Awodey, Mac Lane, etc), so thanks! j2kun's site [2] is highly recommended for anyone looking for a foothold into CT. It begins with a brief look at the universal property of free monoids (by implementing lift for lists), followed by various constructions (many in the category of Set). It (currently) ends with a discussion of map, filter, and (the universal property) of fold. Some constructions/proofs are provided in ML (which I've been meaning to get acquainted with (and while "clunky" is better suited than Haskell for the intended purpose, imo)). So yeah, thanks again! I hope you get time to continue the series...