There’s two things:
You almost always want to use single color engraving as it’s easier to design for and offers very precise control. For example, if you have clip art, you can separately assign engrave settings to each color. But if you have a 3D design that you’ve converted to a heightmap, 3D engraving is the way to go.
wonderful! So, that [single color engrave] makes doing inlays with veneers very easy when the base material is proofgrade - s w e e t 
and my little javascript app may come in useful for 3D engrave situations
Exactly!
Are there any 3D engraved examples?
Haven’t seen one yet, but we’ve been told they’re coming along quite nicely recently. 
I guess it depends on what you mean by 3d engraving, but there are a few examples on the website itself (easy to forget about, I suppose) from several months ago.
That is a functionality that we have yet to see the demo on, but I am hoping in this week’s update that not only shipping dates will be announced, but also what functionality we will expect to see at release
This post is in no way meant to disrespect the Glowforge team, nor anyone dealing with the challenge of being patient and wanting so much more information! It is meant to be a light-hearted expression of my own desire to see some cool stamps made from variably engraved delrin or some other interesting example of the Glowforge magic.
Just as long as you don’t threaten to burn the place down!
