GLs example

[lamelizard]

~~As PR #3 stated~~ (#3's note was about GIs), we do not have an example for GLs yet, is there a good simple example?

We could do the "Eight queens puzzle" with rocks and kings -> allow GWFC to insert some rocks and kings and no piece may be able to hit another piece -> requires 3 GLs (2 for rocks, 1 for kings) but this is boring (but music or art is probably too much code as a simple example?)