Thank you, bagoas. You've suggested what appears to be a workable solution.

I'm especially interested in paragraph 5b: ''... create a spatial function in the (u, v, frame#) domain to do same.  A combination of a paraboloid for u and a trochoid for v, truncated in v, will bring you a long way."

I've found an example of a Poser procedural material that draws an indented grid using "P" nodes and Math_Functions: Multiply, Step, Sin, and Add.

I'm trying to reverse-engineer it now.

Richard