…And these bubbles represent a two-dimensional crystal. They're like atoms all stuck together in two dimensions. This picture was made by Sir William Bragg. Is it focused very well? Can it be focused better? Here are the bubbles on the surface of the... I…

…of the crystal planes or whatever they are for this two-dimensional object. That's the guy who made the picture, Sir William Bragg. And he's illustrating something. I don't know what he's illustrating. Perhaps how crystals might slip over each other. But…