Solve some Takuzu puzzles.
Interesting part is abstracting common parts between row and columns.
Interestingly, Array(Row | Column | Cell) gets turned into Array(Tuple(UInt32?, UInt32?)) which isn't quite what I want.
I wish I could have had this as an enum instead, if the enum variants could have values associated with them.
For example, Row of UInt32 | Column of UInt32 | Cell of Tuple(UInt32, UInt32) - more like data in Haskell.
This code allows m*n grids, even if m != n, as long as both are even.