The "little squares" are the NxN cubes inside the sudoku. For instance if you were given

123 456 789
234 567 891
345 678 912

456 789 123
567 891 234
678 912 345

789 123 456
891 234 567
987 654 654

All the lines and columns are correct. But none of the blocks is (the upper left block hold numbers 1,2,3,2,3,4,3,4,5).

Using Ruby

"Sudoku with invalid boxes (little squares), but valid rows and columns - Expected: false, instead got: true".

What "little squares"? I can't see the data I'm testing against. I'm currently checking to see if a given element is_a?(Integer) so I don't see why this error would crop up.

LOL! I love people like this!!

Why does this work?

Unpack returns an array, and * is just a shorthand method to join the array as a string by the supplied delimiter ('.')

If he really wants 8...