#I6----------------------------------------------
polyline p 0 0 5  0 0 0  20 0 0  20 0 5  
beziercurve bc 4  20 0 5  15 0 6  5 0 4  0 0 5
mkedge bc bc
wire p p bc
mkplane p p
prism p p 0 20 0
profile pf o 12 9 0 p 0 -1 0 1 0 0 l 3 t 0 15 \
t -3 0  
revol pr pf 10 9 0 0 0 1 180
bfuse f p pr
nexplode f f
depouille result f 0 0 1 f_7 1 0 0 15 0 0 1

checkprops result -s 1482.57