#H2----------------------------------------------
bsplinesurf bs \
2 3  0 3 1 1 2 3 \
2 3  0 3 1 1 2 3 \
  0  0 0 1  5  0 0 1  10  0 0 1  15  0 0 1\
  0  5 0 1  5  5 1 1  10  5 0 1  15  5 0 1\
  0 10 0 1  5 10 0 1  10 10 1 1  15 10 0 1\
  0 15 0 1  5 15 0 1  10 15 0 1  15 15 0 1
mkface bs bs
prism p bs 0 0 5
plane pc 7.5 7.5 1 0 0 1
pcylinder pc pc 5 10
bfuse f p pc
nexplode f f
depouille result f 0 0 1 f_7 5 0 0 11 0 0 1

set square 931.411