That was a hard one! with a lot of guessing.. but the final picture is interesting! thanks.

I tried, but it's way too hard. ;(

I tried again and finally got it. That was really tough, but like Miss. Chano said, interesting result!

I've got as far as the three outside rows, but I'm stuck! Any hints?

MMm.. hint..
you have an X (diagonals) in each and all the 5x5 squares on the outsides (outside the 17x17 square).. hope this can help u minimint :)

Thanks Chano - you're a star - I was in the same place as Minimint - but started again and with your hint, it all fell into place!!!

Thank you Chano for your hint :-) Otherwise I didn't have a chance...

Thanks chano big help.

Thank you, Chano, for the hint! =)

Thanks.