%0 Journal Article %A Winston C. Yang %T Adding layers to bumped-body polyforms with minimum perimeter preserves minimum perim\-eter %J The electronic journal of combinatorics %D 2006 %V 13 %U http://geodesic.mathdoc.fr/articles/10.37236/1032/ %R 10.37236/1032 %F 10_37236_1032