Strange Loop talks

There were some interesting Clojure-related talks at the Strange Loop conference a few weeks ago, so we'll be watching one (or more, time permitting) followed by discussion. We'll be picking from these, though other suggestions are welcome!
"Typed Clojure: From Optional to Gradual Typing" by Ambrose Bonnaire-Sergeant
"Unconventional Programming with Chemical Computing" by Carin Meier
"Specter: overcome your fear of nested Clojure data" by Nathan Marz