This may happen sometimes when we do repetitive tasks (any tasks). I found myself designing in my head, with my eyes closed when I’m late in bed at night, I can still move shapes around and create forms, apply gradients and export to PNG. I had to look about it, thinking I was going crazy or I was working too much: it is the Tetris Effect!
The Tetris effect is the ability of any activity to which people devote sufficient time and attention to begin to dominate their thoughts, mental images, and dreams. It is named after the video game Tetris. In the game a player rotates and moves different falling shapes made up of blocks. If the player can arrange the shapes so there are complete horizontal lines of blocks without any gaps, those lines are eliminated. The object of the game is to eliminate as many lines as possible before the shapes fill the screen.
People who play Tetris for a long time might then find themselves thinking about ways different shapes in the real world can fit together, such as the boxes on a supermarket shelf or the buildings on a street.[1] In this sense, the Tetris effect is a form of habit.
So, if you catch yourself walking down the street and mentally, you are still doing what you where doing for the last 72hs, don’t panic! it’s just the Tetris Effect. It happens to designers A LOT for what I heard.
Hey! Good start for 2008!