I love that the simple addition of bubbles make this fully 3d, and with refraction.
Pretty clever. They defocus the laser to heat up the plastic, which then bends (by gravity). Many, many times faster than standard rapid prototyping.
Also has a pen tool for marking cuts by hand.
I like the way it interprets your gesture and regularizes it. Note how this thing leapfrogs over the (obvious?) application of smart-pens-for-CAD, and goes right into fabrication.