I can verify the above objection.

What about this board? Your solution says it's finished, but it clearly isn't.

[[1,2,3,4,5,6,6,9,9],
[4,5,6,6,9,9,1,2,3],
[6,9,9,1,2,3,4,5,6],
[2,3,4,5,6,6,9,9,1],
[5,6,6,9,9,1,2,3,4],
[9,9,1,2,3,4,5,6,6],
[3,4,5,6,6,9,9,1,2],
[6,6,9,9,1,2,3,4,5],
[9,1,2,3,4,5,6,6,9]]

Looks good to me. Maybe you're modifying the original array again!

They work for me: can you check again?

I can imagine that, but in that case, some row/col/square must then fail the test in another part right?

That would work too! I think I did that because I had been playing around with Ruby lambdas too much...

Actually, the "Enumerable Magic" katas are explicitly for beginner exploration.

See previous discussions:

• Enumerable Magic #5
• Enumerable Magic #2
• Enumerable Magic #30
• Enumerable Magic #31
• Enumerable Magic #22