IQ Brain Teaser #171

What should the last grid look like in the sequence below? (HINT: Think squares!) If the boxes were numbered as follows: the last grid would have an X at 1 and an O at 7 an O at 3 and an X at 5 an O at 4 and an X at 6 an X at 8 and an O at 9 an O at 2 and an X at 4 an X at 3 and an O at 8 an O at 6 and an X at 8 an X at 2 and an O at 5 an O at 4 and an X at 9 None of the above are correct view results