Lily Impeller - Biomimicry - Designed by Nature, Backed by Science - video link

Biomimicry is a rapidly growing discipline in which nature’s solutions are adapted to solve man-made design challenges. At the core of the PAX Water Mixer is the Lily impeller, named after its resemblance to the calla lily. The Lily replicates nature’s spiral flow pattern – observed in whirlpools and tornados – to significantly improve the performance and energy usage of mixing water storage tanks. While the Lily is only 8 inches (21 cm) tall, it is capable of circulating millions of gallons of water with the same energy footprint as three 100-watt light bulbs.

http://www.paxwater.com/biomimicry