Scrabble tile checking

Question

For tile checking in scrabble, you make four 5x5 grids of letters totalling 100 tiles. I would like to make one where all 40 horizontal and vertical words are valid. The set of

Answer 1

I'm starting with something simpler.

Here are some results so far:

   3736 2x2 solutions
8812672 3x3 solutions

The 1000th 4x4 solution is
   A A H S
   A C A I
   L A I R
   S I R E

The 1000th 5x5 solution is
   A A H E D
   A B U N A
   H U R S T
   E N S U E
   D A T E D

The 1000th 2x4x4 solution is
   A A H S | A A H S
   A B A C | A B A C
   H A I R | L E K U
   S C R Y | S T E D
   --------+--------
   D E E D | D E E M
   E I N E | I N T I
   E N O L | O V E R
   T E L T | L Y N E

Note that transposing an 'A' and a blank that is being used as an 'A' should be considered the same solution. But transposing the rows with the columns should be considered a different solution. I hope that makes sense.