“Stereo image of this very three-dimensional formation of prismatic honey-coloured baryte crystals. The crystals' tips are covered by a later layer with a rough, etched appearance. How these stereograms work to view the specimen in 3D: Sit straight in front of the screen and look at the image increasingly more cross-eyed. When you do so, the left and right images will gradually start to overlap more and more in the centre. Once you find the sweet spot in which both images exactly overlap, the image will suddenly appear to be in 3D. You can also use the two dots at the top to get the two images to align. This works best if viewed full screen.”