Percy Seymour Douglas-Hamilton of England invented this "Device for Indicating the Intended Movements of Vehicles," possibly the first system of electric turn signal lights patented in the United States.
The application was filed Dec. 31, 1907, and the patent was granted Feb. 16, 1909.
So that other drivers would understand the meaning, the lights were in the shape of hands to mimic the hand signals in common use at the time.