Had this idea back in 2015, If its been done before sry heh looked and couldn’t find anything. I was thinking you could make an engrave and have it key into another for a surface glue joint. doubt it would really be useful but wanted to put it out there to see what people thought.
Now you should break it to see if it’s stronger than an unengraved sheet.
Then glue two sheets face to face and see how strong that is.
Lastly do a keyed butt joint and see where that lands…
Science!
It is really neat, thanks for sharing! I agree, needs a strength test.
I tried that as a face to edge as a “hidden fingers” experiment and it did not do well. I thought @evansd2 had tried to do the same thing and the difficulty of getting a specific depth and a single height bottom in wood worked against you,
Where I think the results could be spectacular is in two colors of translucent acrylic with an LED. Have a way to leave an open area with a dyed oil and glycerine stuff and it could be a mind bending lava lamp!
I tried it on a couple of early designs with the PRU, and abandoned it pretty quickly in favor of other (faster) methods. It just takes so long to engrave compared to the cuts. It is fun to play with though and looks mighty sharp. Someone definitely ought to follow up on it a bit. 
