Totally illogical puzzle. After a huge effort I managed to distinguish the pattern and finally to solve it.
Hint: Every 5x5 square contains an 'x'. The odd ones small and the even Big.

Hint: The odd ones in odd block lines have small and vise versa in even block lines.

OMG what a bad puzzle. Why are people doing this. Please stop.

I kinda like them! Sorry...

I didn't like this. I think it lost the sens of Hanjie. Because it's just mechanical when you get the patch. It bothered me at the begining and later it was so... boring.

Thank you for the hints Tsir1962.

I also thank Tsir1962 for the hints. I am glad to see somebody had the patience to see this one through. And I share Alesko thoughts, I like a challenge but this was just a waste of my time.

Thank you very much for your patience and dedication in solving this one and sharing the solution!

Petits x dans les 5X5 jaunes et X dans les 5X5 blancs