many childrens nightlights work like a simple zoetrope..
they have two shades, each is fitted with vanes on the top. the vanes are angled differently so each shade, turns in alternate directions, from the heat of the lit bulb.

the shades are translucent, with opaque images, -the images travel round and round, the horse over the bush, the gate the river.. the fox always outpacing the horse...

they are rather hypnotic, really..
i am easily entertained... i like lava lamps too