Figure 1
Peter Bertok (

Figure 1: In a scale-invariant system, objects may be found that look the same at all levels of magnification, as in this image of objects called Sierpinski pyramids. The pyramids are made from smaller and smaller pyramids. The papers by Son, and by Balasubramanian and McGreevy, find connections between aspects of string theory and scale-invariant nonrelativistic field theories.