The phenomenon of 'seeing' or imagining Tetris shapes and 'fitting' them around things is known as the 'tetris effect'[0] and is quite common. In my experience you don't need to play Tetris that long to experience it. It's so well known that the Tetris Company named one of their most recent games after it [1].

[0] - https://en.wikipedia.org/wiki/Tetris_effect

[1] - https://en.wikipedia.org/wiki/Tetris_Effect

It's not exactly the same thing, but to this day I hear the Tetris theme whenever I have to do something very stressful (for example, fixing a broken website with the CEO on my back).

I adopted it and now hum it to relax.

Interestingly, I'm pretty high on the aphantasia scale, so maybe it's just my brain's way of playing the "tetris effect."