cylinder surf 1
trim surf1 surf 0 1 -1 1
convert surf1 surf1
mkface f1 surf1
trim surf2 surf 1 2 -1 1
convert surf2 surf2
mkface f2 surf2
trim surf3 surf 2 3 -1 1
convert surf3 surf3
mkface f3 surf3
trim surf4 surf 3 4 -1 1
convert surf4 surf4
mkface f4 surf4
sewing sh f1 f2 f3 f4
cylinder cyl 0 0 -2.5 1 0 0 3
trimv cyl1 cyl -2 2
mkface fcyl cyl1 
nurbsconvert fcyl fcyl
bsection ss fcyl sh
explode ss e
shape w w
add ss_1 w
add ss_2 w
add ss_3 w
add ss_4 w
add ss_5 w
getanasurf asurf w cyl 1.e-7 cyl
if {[isdraw asurf]} {
  set log [dump asurf]
  if { [regexp {CylindricalSurface} $log ] != 1 } {
     puts "Error: surface is not a cylindrical surface"
  }
  if { [regexp {Radius :3} $log ] != 1 } {
     puts "Error: surface is not a sample surface"
  }
} else {
  puts "Error: required surface is not got"
}