Abstract
Of all Plateau borders (PBs) that may be realized in an equilibrium two-dimensional wet foam, we identify the class of ‘decoration PBs’ as those for which the (circular) film prolongations into the PB meet at the equilibrium angles at a single point. Any three-sided PB is a decoration PB, but this is, in general, not true of n-sided PBs with n > 3. For decoration PBs we define an excess energy as the difference between the energy of the PB surfaces and that of the film prolongations into the PB. We analyse arbitrary three-sided PBs and show that their excess energy ε 3 is approximately proportional to their linear dimensions. We further investigate the ratios