Yup, I've wanted to make something like this. There's focus vs creativity periods. The brain focuses better when tired, but people's cycles are very different.

Yup, I've wanted to make something like this. There's focus vs creativity periods. The brain focuses better when tired, but people's cycles are very different. So it's best to just prompt them how they feel periodically and whether the task was a good fit. This is similar to how they did the research that uncovered the concept of being in flow.