... can be used as guide line for solving contour.
Will leave it as is, unless some question arise.
Smath solve(2) is most interesting, maybe for more applications.

Jean

Contour SOLVE [at(2) LIMITS].sm (29 KiB) downloaded 74 time(s).
Contour SOLVE [Electron Publish].sm (24 KiB) downloaded 67 time(s).
Contour SOLVE Tom MCD.sm (199 KiB) downloaded 76 time(s).
Contour SOLVE [user ColorMap].sm (310 KiB) downloaded 75 time(s).