TRAVIS LOLLER and STEPHEN SMITH.

It is Carnival season in New Orleans. That means gazillions of plastic green, gold and purple beads are being tossed to crowds. But the beaded necklaces are increasingly seen as a problem. Despite efforts to collect them for reuse, many are trashed or left on the ground. A few years ago, the city pulled 46 tons of them from its storm drains. This year, three krewes are throwing biodegradable beads instead. Developed at Louisiana State University, the “PlantMe Beads” are 3D-printed from a starch-based material. The individual beads are hollow spheres containing okra seeds. That is because the necklaces can actually be planted, and the okra attracts bacteria that help them decompose.