The first solid we can make is a Tetrahedron, made up of four triangles. You can think of this as like a pyramid, though most pyramids have square bases so they don’t really count. Imagine it as a triangular pyramid, though, and here it is.
The first people to write about these shapes were the ancient Greeks, so we describe them with names based on the ancient Greek language. The name Tetrahedron is derived from the words Tetra, meaning four‘, and hedron, meaning face or side.