pcylinder c1 2 5
profile p x 2 y 2 x -2 y -2
trotate p 0 0 0 1 0 0 90
ttranslate p -1 -4 4
explode c1 f
mksurface f c1_1
mkface f f

featprism c1 p p 0 1 0 1 1
featperform prism result f

set square 109.383
