ROKR celebrates great mechanical breakthroughs with the Industrial City Series, a line of ROKR 3D puzzle models inspired by early industrial machinery. The collection includes the Morse Telegraph, the Oil Rig, and Da Vinci's Helicopter, each one able to operate independently but can power up in sync through a shared hub or wired tracks. Connect them all to create your very own desktop industrial city. These inventions were once envisioned by great minds, eventually becoming the foundation of some of the technology we use today. Da Vinci's aerial screw, in particular, introduced the idea of vertical lift through rotational motion, the same concept behind today's helicopters. Keep dreaming, because just like Da Vinci's Helicopter, imagination has the power to defy gravity.