The Surface Evolver has been used to minimise the surface area of
various ordered structures for monodisperse foam. Additional features
have enabled its application to foams of arbitrary liquid fraction.
Early results for the case of dry foam (negligible liquid fraction)
produced a structure having lower surface area, or energy, than
Kelvin's 1887 minimal tetrakaidecahedron. The calculations reported
here show that this remains the case when the liquid fraction is
finite, up to about 11\%, at which point an f.c.c. arrangement of
cells becomes preferable.