This example looks like contour.tcl example, but it contains 2 set of contours: "lower " set and "upper" set. Upper set of contours is shifted up at 0.2. The resulting surface is between these contours sets.

See Also
contour_leq, contour_geq, completer
Here is the image of the resulting surface:

surface built from areas

Pic 1. Surface built from contour inequalities

This result was obtained with "examples/surfit/curvs/contour_ineq.tcl" script.

surfit: gridding and contouring software.