A Starry Sky

This picture looks like the night sky full of stars, but contains something completely different hidden in it. Try to focus behind the picture and see what appears!

If you have fairly equal sight in both eyes, you can try to find the hidden picture by directing your gaze such that your eyes look in parallel directions. Some people find it helps to look at the two white dots under the picture first. After a while there appears to be four, and then the two in the middle merge and there now appears to be three dots. If you can now raise your gaze and look at the picture of the starry sky without starting to focus on it, you can find the hidden image.

Other people can make it work by first looking at the picture from a very close distance such that everything is blurred, and then increasing the distance to approximately 50 centimeters. If you can do this without changing focus, the hidden image usually appears.