We’ve been using pigments and dyes for thousands of years, but they’re not the whole story when it comes to making color. “Structural” color occurs when tiny nanostructures interact with light waves, amplifying certain colors and canceling others. From brilliant bird feathers to butterfly wings, mole hairs to octopus skin, structural color is everywhere in the natural world. Researchers have tried for years to harness this incredible natural phenomenon in a useful way. Because these colors are so small and complex, and therefore hard to copy, their efforts have met with little success. But novel research using a computer model based in repeated random sampling — a so-called “Monte Carlo” model — is showing promise. Using this approach, scientists have been able to mimic the gorgeous blue of the mountain bluebird in a thin film of reflective beads, leapfrogging millennia of evolution.