<image>In the cuboid ABCD-A1B1C1D1, with AB=1 and AD=2, if there exists a tetrahedron P1P2P3P4 with equal edge lengths, where P1, P2, P3, and P4 are respectively on the lines containing edges AB, A1B1, C1D1, and CD, then the volume of this cuboid is __.
