polyline p 0 0 0 10 0 0 10 0 7 6 0 7 6 0 3 5 0 5 0 0 5 0 0 0
mkplane f p
prism s f 0 10 0

OFFSETSHAPE 3 {} $calcul $type

checkprops result -v 3136

checknbshapes result -shell 1
