This Demonstration shows a visual proof that the volume of a generalized rhombic dodecahedron of the second kind (RD2, or Bilinski dodecahedron) is , where and are diagonals of four congruent rhombuses. This is shown by moving the pieces of the dodecahedron into a cuboid (rectangular prism, or box). The 12 rhombic faces are congruent only in the RD2 case.