cube([60,79,15]);
translate([0,0,15]) cube([15,79,45]);
polyhedron(
    points=[ [15,33,15],[60,33,15],[15,33,60],
               [15,46,15],[60,46,15],[15,46,60] ],
    triangles=[ [0,1,2],[0,3,5,2],[3,4,5],[0,1,4,3],[1,4,5,2] ]);