Thin-film interference
When a monolayer of densely packed spheres is used as a mask for nanolithography, the spheres sometimes pack into several layers. The result can be beautiful thin-film interference—as in this example, reminiscent of a Hokusai lithograph.
—O.A. Lozhkina, V.V. Shilovskikh and Yu.V. Kapitonov, St. Petersburg State University, St. Petersburg, Russia