Double-Friauf polyhedra (DFPs) which play important roles in quasicrystal (QC) models are the unique building blocks in the novel 1/0 AC, CaAu3+Delta Ga1-Delta (Delta approximate to 0-0.13) [Pa (3) over bar; a = 9.0875(3)-9.1107(5) angstrom]. The packing of DFPs generates interpenetrating networks of condensed three-dimensional Penrose tiles, the geometry of which is close to that assumed for QCs.