3D pictures + Magic Eye

As a very young child, every week, I had to practice for one hour minimum 3D pictures.

I will share a few now here, what I found on the internet.

But before a short intro of autostereogram:

https://www.vision-and-eye-health.com/autostereograms/

"What are autostereograms?

Autostereograms are two-dimensional (2D) images with repeating patterns that hide an underlying three-dimensional (3D) image.

A picture within a picture, so to speak.

They are not the same as stereograms. Stereograms require the use of a stereoscope for the 3D image to be seen.

Autostereograms, on the other hand, do not require a stereoscope. The hidden 3D image can be seen with just the naked eye, as long as the correct focus can be achieved.

When you look at an autostereogram, your brain initially sees repeating 2D patterns from both eyes. This is because your brain automatically focuses on the image itself.

When you are able to focus your eyes behind the 2D pattern, your eyes start to look at the pattern at a slightly different angle. At this point, your stereopsis kicks in and your brain is able to construct the 3D image at a depth different to that of the 2D pattern.

A brief history of autostereograms

Stereograms were first discovered by Charles Wheatstone.

In 1838, he combined mirrors and lenses to create the first stereoscope. The stereoscope allowed a single 3D image to be seen from two slightly different and disparate 2D images.

The autostereogram was first conceived by Christopher Tyler in the 1970s. Using computers, he was able to combine the different visual theories to generate the first random dot stereogram that allowed the brain to perceive 3D from a single 2D image without any optical help.

In the 90s, there was a huge surge in the popularity of 3D autostereograms. This craze was sparked by Magic Eye 3D pictures published in the United States. Magic Eye books have now sold more than 25 million copies worldwide and have been released in over 20 languages."