If you like stereograms, to make or just to see, please vote for the stereogram group.
A link to another tutorial that teaches how to see 3 d http://www.colorstereo.com/texts_.txt/practice.htm
If you want to see this 3 d make sure the images is small, then try looking at it without looking at it, stare in the distance, the images will start to moove and if ot works for you they suddenly pop in to place and give you depth.
It can be tricky to learn to unfocus your eyes as this is not something you usually do.
One exercise is to hold up your finger and look at at, now switch your attention and look far away at the room you are in, you can still see your finger but it will be not a clear image, you will see more than one finger, parts transparent and parts not.
This is exactly how it works with this sketch, if you look through it into the distance you will get these confusing images, if you give your eyes time they will try to make something out of it.
Suddenly you see in the middle of your vision a clear image with lots of depth.
If it does not work for you try holding the image closer to or further away from your eyes.
It needs a bit of prctice and patience but if you can't be bothered ;-) or just can not get it to work,
just enjoy the sketch.
Many thanks to pomander, who taught me how to do this.
Here is the link to the tutorialhttp://app.sketchclub.com/sketch/10910562
I used my personal photo as reference
What is the best way to deal with the empty space in the middle?
I started the background at zero, so I had just the positives to work with, that is a lesson learned