They were big in the 90s, we called them ‘Magic Eye’ pictures but the real name for them is: Stereograms. Some people HATED them, but only because they couldn’t do them! They look like a 2D pattern, but it you focus (or unfocus) your eyes in just the right way, you see a hidden 3D image. If you’ve forgeotten the knack, here’s a reminder;
1. Put your face close to the screen (or the printed stereogram).
2. Hold the stereogram horizontally.
3. Move slowly away from the image (or move it slowly away from you)
4. The patterns will start to blurr
5. After a few seconds (or minutes if you’re new to this) you will see a new image emerge, it will become very sharp.