[choult]

I've experienced this before - not only with games such as Tetris (I could "feel" my brian working in a different way) - but also with looking at trees etc when engrossed in Lindenmayer Systems [1] that I was working with at the time.

I assumed it was basically something along the lines of your brian adapting to a "new" reality/situation and engaging the pattern-matching parts that work best for the challenge at hand. Then afterwards it remains on just in case you need it again, like a warm boot.

As I type about it, I realize it likely has relation to things like anxiety - useful in some situations (such as actual danger) but remains "on" when it doesn't have to and becomes intrusive.

[j4coh]

I get something similar after long days at music festivals where if I close my eyes later I still see people walking past.

[ajuc]

After I tweaked the tree outline drawing algorithm for this side-project for like 20 hours over 3 days ( https://ajuc.github.io/outdoorsBattlemapGenerator/ ) I've been seeing these outlines EVERYWHERE :)