polyline w 0 0 25  20 0 5  5 0 5  5 0 -5  20 0 -5  0 0 -25  0 0 25
mkplane w w
revol s w 0 0 0 0 0 1 270
tscale s 0 0 0 SCALE1
explode s E
mkevol result s
updatevol s_8 0 1*SCALE1 1 2*SCALE1 2 1*SCALE1
buildevol

set square 555384