Superegg (nonfiction)

Superegg rendered in brass.

In geometry, a superegg is a solid of revolution obtained by rotating an elongated superellipse with exponent greater than 2 around its longest axis. It is a special case of superellipsoid.

Unlike an elongated ellipsoid, an elongated superegg can stand upright on a flat surface, or on top of another superegg. This is due to its curvature being zero at the tips. The shape was popularized by Danish poet and scientist Piet Hein (1905–1996). Supereggs of various materials were sold as novelties or "executive toys" in the 1960s. A 1-ton superegg made of steel and aluminium was placed outside Kelvin Hall in Glasgow in 1971, on occasion of a lecture by Piet Hein.