A light-based
hump semaphore (light-signal) consists of
the pole (usually painted black or grey, though the
Rules don't say anything for that), and the head with
seven small white light-cells. The definite
hump-shunting orders are given by a combination of
these white lights.
A shape-based
hump semaphore (classic, mechanical)
consists of the pole and a white narrow
rectangle-shaped rotating part, mounted on a round
black plate. The white rectangle can light during the
night.
The definite
hump-signal is reflected by the proper position of
the rectangle.
