This is really great. A zero-installation CLJS notebook would have already been cool, and Maria has that, powered by (defcell). It also has the shape library,

This is really great. A zero-installation CLJS notebook would have already been cool, and Maria has that, powered by (defcell). It also has the shape library, which makes playing around with higher-order functions more intuitive to understand than just seeing a series of numbers as a result. It can also output HTML!