GeomLab and Mindstorms
GeomLab has a turtle graphics feature, but the pictures are drawn only on the screen. It should be possible to make a turtle out of Lego Mindstorms, then control it with an instance of Geomlab running on a host computer, with communication over Bluetooth.
Please see http://spivey.oriel.ox.ac.uk/corner/Undergraduate_and_M.Sc._projects for further details.
N.B. This project is not available to MSc students in 2016-17.
Undergraduate students who wish to enquire about a project for 2017-18 are welcome to contact Prof Spivey but should note that the response may be delayed as he is on sabbatical.