- Pacific Plate (Wikipedia)
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million km2 (40 million sq mi), it is the largest tectonic plate.
- Tetrahedron (Wikipedia)
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.