Called a Gyro-Ray, these were fairly popular (mostly in the northeastern part of the country) from the mid-1960s through the early 1970s. Two bulbs are stationary while the third moves up and down as it rotates:
[ame]http://www.youtube.com/watch?v=3lNVdFKl6Oc[/ame]
[ame]http://www.youtube.com/watch?v=3lNVdFKl6Oc[/ame]