(color online) The schematic drawing of the manufacture method of the hollow corner cube retroreflector: (a) before bonding and (b) after bonding. Mirror 1 is the base mirror; mirrors 2 and 3 are the lateral mirrors. Mirrors 2 and 3 are completely separated by a tiny gap. α₂ and α₃ are the perpendicularities of mirror 2 and mirror 3, respectively. β₁₂, β₁₃, and β₂₃ are the dihedral angles formed by mirrors 1 and 2, mirrors 1 and 3, and mirrors 2 and 3, respectively.