Quick summary (step-by-step / more details in video):
1. Attach .001" steel shim to cast acrylic sheet with mounting tape (leave paper backing on acrylic)
2. Cut out though-holes and board itself at 6.5 mm/s (2 passes)
3. Cut traces at 15 mm/s (2 passes)
4. Peel off non-trace segments from board surface (including tape and paper backing)
5. You have a circuit board!
Fast - can make a simple board in only a few minutes
No chemical etching needed
Boards can be any color acrylic comes in - including transparent!
Laser can be used to cut through-holes / cut the board out in any shape
Steel isn't a great conductor / may be an issue for some circuits
Boards are not as sturdy as etched ones
Traces limited to minimum of around 1/16" wide - not suitable for SMD
Soldering smaller (DIP) components can be a bit finicky
More details at www.nothinglabs.com