They also use totally different mechanical concepts to move the pieces. The Phantom uses an etch-a-sketch style 2 access CNC machine with a magnet head embedded in the board (I think). For the Chessnut, each of the pieces are their own little micro robot that can drive around the board surface. Really neat to see different mechanical solutions to the same automation problem!

that is so amazing! yeah my "solution"-- yeah, let's call it that: i spent 15mins thinking about it, so now i'm an expert!-- was a lot closer to the Phantom solution... driving the pieces around on the board autonomously seems absolutely insane, and i'm here for it.