Are there sentences which are locally consistent[1] but globally impossible?
(the question is on my mind because earlier on HN I'd had a nice convo about a folk song embedded in a protest song in which the quoted verse worked nearly as well as polish under a functor as in the original ukrainian.
https://news.ycombinator.com/item?id=24101696 )
[1] on a longer scale than "colourless green ideas sleep furiously", of course.