This image, taken inside the Tokamak Seismic Pit last Tuesday, is an "anaglyph." It was made by combining two slightly offset and differently filtered photographs into one single image. When using 3D glasses (with a red filter on the left eye and a cyan filter on the right eye), the visual cortex of the brain fuses the two images into one, creating a three-dimensional perception of the scene.

The alignment of plinths on the floor of the Tokamak Seismic Pit offered Jean Jacquinot, former director of JET and photography enthusiast, with a perfect setting to try the anaglyph technique.