Regarding the LOGO usage of "turtle": There actually have been real robot turtles that draw pictures according to computer instructions. I think MikroBitti once had a picture of one pretty specimen; It looked like a real, if rather stylized, turtle, and best of all, it was wireless - the computer controlled it over infrared link (the "shell" of the turtle was made of transparent green plastic, with the IR sensor and all electronics inside it).
In August 1972, during one ICCC demonstration, Jon Postel was puzzled by such turtle - it had went crazy, jumped around and twitched. (Postel had printed a file to wrong printer port, instead of sending it to printer it had gone to turtle port...) a true ninja turtle...
(the latter story, along with what else happened in the demo, can be found in book Where Wizards Stay Up Late, by Katie Hafner and Matthew Lyon.)
Speaking of the book Small Gods, Om, as a tortoise, also draws pictures to sand with His tail according to instructions of people. The book also refers to these LOGO turtles...