- In geometry, a tetrahedron (pl.: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertices. The tetrahedron is the simplest of all the ordinary convex polyhedra.
- Shaula (stars.astro.illinois.edu)
SHAULA (Lambda Scorpii). In temperate northern summers, Scorpius glides above the southern horizon, its lower curved tail almost out of sight, while in the temperate southern winter, the constellation passes high overhead. At the end of the tail lies a pair of stars that represent the scorpion’s “stinger,” once called Shaula, from Arabic meaning exactly that.
