this is so incredibly satisfying. great concept for a little game. 5/5
the gentle music being a background to the click clack is also great!
EDIT: I will say that the last line feels a bit off. I had all but 3 of them unlocked and yet it was still 4-5x better to turn off the entire last line. The other lines were always worth it after you had reached the point of 2-3 of them.
EDIT2: i tried turning the bottom layer back on after a few more upgrades and it crashed :D