User-facing state is what someone experiences when they interact with (or try to interact with) an element in some capacity.

Despite being a cornerstone in the community, Goodreads has continually disappointed its ample user base with bad usability.

Creating software to reconstruct one-line drawings.

Generative mountain ridge dividers using videogame terrain generation techniques, JavaScript and SVG.

There are many use-cases where an interaction (click/gesture) on one element toggles a ‘state’ that can be shared with other elements.