I know from experience that I am capable of working productively for 10+ hours continuously on a single project but this extreme flow seems to only happen under

I know from experience that I am capable of working productively for 10+ hours continuously on a single project but this extreme flow seems to only happen under extremely specific and not easily reproducible circumstances that generally run counter to overall "productivity" (ie: It is usually late-night work on a pointless hobby-level program). I have occasionally in my career so far had an alignment of just the right problem, just the right guidance, just the right solution, and just the right deadline to facilitate 8-uninterrupted-hour-skip-lunch-"in-the-zone" programming days. I would assume those stories about founder geniuses are partially-exaggerated versions of that played out over a larger scale and with a more deliberate focus on facilitating that type of perfect alignment of problem & solution.