||
Can't help but think I missed a lot of obvious-in-retrospect and mostly-realistic ways to get something there.
...
comments/notes after reading others' answers:
marblespuzzle.com (dead link) is the most simple and pure example of a puzzle game I know of, and is one of my favorites.
Playable in the time machine:
https://web.archive.org/web/20190909085700/http://marblespuzzle.com/
Baba is top tier, but in some levels the character movement eats much more time than the puzzle solving; the idea of blocks or tokens that predictably change things based on which other blocks are nearby can be taken much, _much_ further.
To loosen mental constraints around language a little bit: How you push-data-out doesn't need an obvious or direct map to how you pull-data-in. This is already true in the usual cases: Ears don't speak and mouths don't hear (but they're either writing to or reading from air pressure directly). Pens don't read and eyes don't write (but they're working with the same low-level-language of "how stuff looks").
I'd like to show that there can be a more obvious difference between how we generate symbols and how we receive symbols. Examples: