You can work on a project, or you can work on a tool to make that project easier. A work-station, a jig, a library, a pod orchestration framework. Sometimes the new thing you've made will make the target project easier; sometimes you go down a rabbit hole and forget the project you were supposed to be working on as you start designing a new language to write a library in to write a database with that would suit your new project a lot better than SQLite.
Open any wood-working magazine, and half the projects are workbenches and shop organization.
