Lone Waves That Won't Stop
The popping lid of a jam jar is the hero of this story. Press it, and with a loud click it flips from a convex to a concave shape. Exactly the same happens with a hinged beam inside each cell of a new mechanical lattice.
Scientists assembled these snapping beams into a hexagonal grid, like honeycomb, but made of elastic plates. When one beam is sharply compressed, it snaps and pushes its neighbor.