in geometry, the great ditrigonal icosidodecahedron (or great ditrigonary icosidodecahedron) is a nonconvex uniform polyhedron, indexed as u. it has 4 schwarz triangle equivalent constructions, for example wythoff symbol 3 | 3 5/4 gives coxeter diagram = . it has extended schläfli symbol a{5/2,3} or c{3,5/2}, as an "altered great stellated dodecahedron" or "converted great icosahedron".