beziersurf bsurf 3 4  0 0 0 2  10 0 5 1  20 0 0 2  0 10 2 3  10 10 3 1  20 10 2 3  0 20 10 1  10 20 20 1  20 20 10 1  0 30 0 2   10 30 0 1   20 30 0 1
offset bsurf_of bsurf 5
offset r bsurf_of 5
set MaxFTol 9.9999999999999995e-08
set MaxETol 6.0150939702465477e-07
set MaxVTol 6.0150939702465499e-07