Extended conjugate roof is defined in the same way as normal conjugate cones.
For subset A of standard lattice L3, XRoof* A is …
As shown below, XRoof* A is obtained by putting as …
In this case, eight cubes are put on XCone* A (A = {x1lx2mx3n, …}) to obtain XRoof* A which is equal to XCone* { x1l-1x2m-1x3n-1, …}.