A tetrahedron, the simplest of all platonic solids, before the hexaedron and the dodecaedron, is a pyramid with a triangular base. It is made of four triangles. It you truncate it properly, four extra triangles appear. Its now just a matter of properly rotating, thickening, connecting, smoothing, carving these eight triangles to get this nice little thing, a very old design, also known as Ora.
Other smoother and smaller versions are available: