This is really a spin-off from Impact Engraving and my delving into half-tone techniques.
A pair of interesting little free programs I have stumbled across are ‘Reactor’ and ‘Halftoner’ written by Jason Dorie (Mach user). These are just so incredibly simple to use and yet produce some most unusual results. With the output in .jpg format from Reactor this can be converted to either a GCode toolpath or dot drill with VcarvePro or similar whilst Halftoner will output a Mach compatable GCode or a .dxf as you chose.

This styled engraving of, the now departed, Amy was made with Reactor as an outline toolpath but equally could have been done as a V groove.

Tweakie.

http://www.youtube.com/watch?v=xoJDTPRqI6o&feature=player_embedded

http://jasondorie.com/page_cnc.html

And this is the same image processed with Halftoner using the 'line' option and cut into particle-board with a V bit (It really needs colour filling to enhance the contrast but I just don't have the time today).

Tweakie.