Any reason why this is implement as a hex instead of the traditional crossword style?
There isn't a technical reason why the traditional crossword format can't have clues in the shape of regex right?
There isn't a technical reason why the traditional crossword format can't have clues in the shape of regex right?
As far as I can tell, the puzzle is fully constrained.
From the start, the bottom-left cell as well as the right column can be solved just from the starting hints, and then you can derive the top-left cell per the backreference.
In particular, you can reframe the right column's hint as (AB|OO|OR), and only one of those satisfies the bottom row's hint.
Something as simple as "OO\nDO" should be valid. But also "OO\nDD" and myriad other solutions.
edit: and by full match (since this seems to be the source of some confusion in another subthread), I explicitly mean anchored with your \A...\Z or whatever you want to use.
They just went the extra mile to make an special puzzle.