Answer:
If you haven’t found the 6 yet, here is the solution. In the middle of the image, slightly to the right and a bit down, the number 6 is hidden among the 9s. It really takes a sharp eye to spot it within 6 seconds!

This illusion tests not only your eyes but also your ability to quickly notice subtle differences. If you found the 6, congratulations! That means you have an excellent eye for detail and possibly a high IQ. Challenge your friends and family to see if they can find it within the time limit too!