Indoor Sundial: The Bulbdial Clock

(repost from ironic sans)

"I think we can all agree that sundials pretty much suck. They only have an hour hand, they don’t work at night or indoors, their accuracy changes with the seasons, and if you happen to live in the Southern hemisphere they run backwards. And yet, we all would love to be able to tell the time by looking at shadows, right?
That’s why I’ve come up with the Bulbdial Clock.

The Bulbdial Clock has no hands — just one pole in the center of the clock, and three light sources of varying heights which revolve around the pole casting shadows. In the model illustrated above, the light sources are each attached to a ring which rotates around the pole. The innermost ring rotates once per minute, casting a “second hand” shadow. The middle ring rotates once per hour, and casts the “minute hand” shadow. And the outer ring rotates once every 12 hours, casting the “little hand” shadow.
The Bulbdial Clock can be used flat like a traditional sundial, or mounted vertically on a wall. A variation on the design intended for large-scale installation (such as in a museum) involves a pole sticking up in the middle of a room, while the light sources are mounted on the ceiling, shining down on the pole as they rotate around it.
The Bulbdial Clock solves most of the sundial’s problems, but it still has a problem of its own: It doesn’t work in bright light. So the Bulbdial Clock is best suited for dim spaces such as restaurants and nightclubs."