Learn clojure.spec (cljs,spec) interactively

There is one fantastic tool called klipse which allows you to run Clojurescript interactively in the browser. It is even more helpful when it allows you to learn something like clojure.spec by examples that actually run in realtime and which you can change and see how everything works: http://blog.klipse.tech/clojure/2016/05/30/spec.html