In every scheme 10x10, in every row and column must be inserted 5 white cells and 5 black (or other symbols, I have used the numbers 1 and 2 to be faster).
The other only rule to be respected is that in row and column you can have at the most two consecutive cells of the same type.
It comes out from there a puzzle not banal, try it and let also some friend of ours to try it, you will see that it reserves some surprises
24m33s, my time to solve it
very easy
easy
