Great icosacronic hexecontahedron  In geometry, the great icosacronic hexecontahedron (or great sagittal trisicosahedron) is the dual of the great icosicosidodecahedron. Its faces are darts, having two angles of formula_1, one of formula_2 and one of formula_3. Its dihedral angles equal formula_4. A part of each dart lies inside the solid, hence is invisible in solid models.