"In condensed matter physics, Hofstadter's butterfly describes the spectral properties of non-interacting two dimensional electrons in a magnetic field. The fractal, self-similar, nature of the spectrum was discovered in the 1976 Ph.D. work of Douglas Hofstadter[1] and is one of the early examples of computer graphics. The name reflects the visual resemblance of the figure on the right to swarm of butterflies flying to infinity. It is one of the rare non-random fractal structures in physics, along with KAM tori.[citation needed] The Hofstadter butterfly plays an important role in the theory of the integer quantum Hall effect, and D.J. Thouless has been awarded the Nobel prize in physics in 2016 for the discovery[2] that the wings of the butterfly are characterized by Chern integers[3], the quantized Hall conductances discovered in 1980 by Klaus von Klitzing for which he has been awarded the Nobel prize in 1985. The colors in the diagram reflect the different Chern numbers."

Thanks, that's pretty interesting, and somewhat relevant to the article.