The
Rhombicuboctahedron is an Archimedean solid. This version is a partially expanded cube as 12 of the 18 faces that would normally be exact squares are rectangles instead. These geometries were chosen as this version fits perfectly nested within a cube. Take a look at 0:32 of the attached video. See also
Nested Building Blocks 1.27 x 1.27 x 1.27 inches