Nanobot Loop

Loop is part of the Nanobot universe.

A conveyor carries lettered blocks out of order, and you have to spell a word with them. You never touch a block. PUSH puts the next block on a pile, and POP takes back whichever block went on last. Push three in, pop them straight out, and they come back reversed.

Knowing when you want that reversal, and when you have to avoid it, is the whole game. Later chapters add longer conveyors, tighter piles and a second pile to choose between.

Play on iOS, 288 levels:

https://apps.apple.com/app/id6801324977