[Sohcahtoa82]

I know this is Hacker News, and so someone "working on something" on their own is typically interpreted to mean "building a startup", which I would still call "work" in the more classic meaning of employment, but "work" doesn't have to mean that.

A friend of mine retired early and spends a lot of time in his workshop building fun things for himself. That is work, but it's not "work" in the way people think of the term.

One project I want to do some time is design and 3D print a model roller coaster, including building a train to travel over it. That's work, but it's not employment.