Instructions about how to view 4D images:
You only need a pair of red/blue(cyan) 3D glasses.
Most images are three dimensional but some have this symbol:
This image will be 4D. This means the difference between what each of your eyes sees is not only perspective (which create the sensation of depth) but also time.
‘afte’ means this is the later of the two images.
‘b4’ means this image is set in time before the image in the other eye.
Some images are 4D but don’t have this symbol because the time lapse is not a feature of the image. The following image is an example. Each moon image is actually two images each a day apart. Over the 24 hours the moon has turned slightly so when each image is assigned to different eyes the shape of moon is enhanced for us.