This one is based on the earlier "Get Even" where you had to find one "2" in a 7x7 grid. Now the game is turn based, and there are three hidden "2"s.

There's a bit of memory needed, like "Old Maid". Some (very) basic knowledge of prime numbers will help as the non-"2"s are all primes, with "3"s being adjacent to "2"s and "19s" far away.

[1]: Grey-haired back-end dev.