It's a haptic pen, like: https://www.3dsystems.com/haptics https://www.3dsystems.com/haptics I got to play with one at SIGGRAPH 96 (!) and it was a really coo

It's a haptic pen, like: https://www.3dsystems.com/haptics https://www.3dsystems.com/haptics I got to play with one at SIGGRAPH 96 (!) and it was a really cool experience. It really does feel like the tip of the pen is sliding over an invisible surface.