Alexey Kavokin

The pendulum of an old clock swings because a spring mechanism gives it a regular nudge. Now imagine a pendulum that decides on its own when to swing, and does so with a steady rhythm, just because the room is warm and there's a slight draft. That's exactly how time crystals behave, born in clumps of light and matter inside a semiconductor chip.

Light gets trapped in a crystal lattice, but not an ordinary one: it's turned inside out, like a honeycomb where instead of wax there's emptiness, and the edges are made of material. That's how an inverted opal is built: a three-dimensional photonic crystal that blocks light of certain colors.

A snow-covered mountain slope looks like a chaotic jumble. But measure the roughness and you find that the height variations follow strict mathematics. Stochastic modeling shows these random processes aren't entirely random. They produce universal patterns, whether in snow, the flame front of a wildfire, or the growth of a bacterial colony.