Solved Problem 11 in Haskell
Move specific top-level functions into where clause in Problem 11
Add an alternative solution to Problem 11 in Haskell

This solution uses 4 rectangular stencils (horizontal, vertical, diagonal left, diagonal right) to extract selections from the 2D grid.
Put "where" on the same line

Indent the contents of the where clause on the line after the "where" keywrod.
Construct diagonal slices more intuitively in Problem 11 Haskell

Wrap the grid elements in Just, stagger the list with Nothing, transpose it, then remove the Nothings
Abandon the alternative based on stencils for Problem 11 Haskell
Replace map (map read) with map2D read in Problem 11 Haskell
Use catMaybes to filter out Nothings in Problem 11 Haskell
Refactor Problem 11 Haskell
Convert map2D to pointfree