Great icosahedron

The great icosahedron, or gike, is one of the four Kepler-Poinsot solids. It has 20 triangles as faces, joining 5 to a vertex.

Retrosnub tetrahedron
The great icosahedron can also be considered to be a kind of retrosnub tetrahedron, by analogy with the snub cube and snub dodecahedron. It is the result of alternating the vertices of a degenerate uniform polyhedron with 8 degenerate hexagrams and 6 doubled-up squares and then adjusting edge lengths to be equal.