Here’s the SVG file for this test so you can see how it’s set up. It’s actually very simple because one side of the joint (yellow) is just a cut pattern, and the other side (orange) has linear gradient bevels.
The width of the bevels/cuts in the dovetail should be equal to the thickness of the mating material for a flush finish, or not equal if you dont want a flush finish (might be cool with either protruding or recessed look, hmmm!). Some folks might want to adjust for the laser kerf to make a really snug joint, I did not bother with that for this test because of simplicity. Instead I drew lines that would line up perfectly and relied on the kerf to give the clearance to allow it to fit.
In the file, I added dotted lines as visual reference to show the parts of the two mating pieces that line up with each other.
Also, because the GFUI doesn’t read vector gradients yet, the gradients over the orange part’s cutting path are a bitmap. The vector gradients are off to the right side because I like to keep vector sources for easier updating.
This is only a 1" square so the whole job ran in a minute and a half. Still, I am impatient and feel the need to stand in front of the glowforge and rest my chin on the lid while watching it work. 
5 year olds got nothing on this 41yr old manchild.
Dovetail Joint.svg 2.zip (2.5 KB)