Overview: (a:) A position-correcting tool. The device consists of a frame and a tool (in this case a router) mounted within that frame. The frame is positioned manually by the user. A camera on the frame (top right in the figure) is used to determine the frame’s location. The device can adjust the position of the tool within the frame to correct for error in the user’s coarse positioning. (b): To follow a complex path, the user need only move the frame in a rough approximation of the path. In this example, the dotted blue line shows the path that the tool would take if its position were not adjusted; the black line is its actual path. (c): An example of a shape cut out of wood using this tool.