National Geographic: Two brothers, Levi and Corban Tillemann-Dick of IRIS Engines Inc, are carrying on their father’s dream of designing a smaller, lighter, and more efficient automobile engine. Unlike the traditional internal combustion engine, which drives pistons, their award-winning Internally Radiating Impulse Structure drives flanges that open and close like the iris of an eye. Compared with pistons, the flanges have a larger working surface area, which increases efficiency while reducing waste heat.