If you have a copy of the book Harbincadabra, you will find a description of this effect. A pole of bamboo 8 1/2" long has four separate strings threaded through holes drilled through spaced about 1" apart. The strings have a different colored bead fastened to each of the 8 ends and when a string is pulled through the rod the string changes color to that of the bead.

I personally have never seen one of these before and it is a curious device. On the bottom side where the holes are drilled the bamboo is opening slightly with the grain. Includes the illustrated instructions from Harbincadabra. The action is not the smoothest but it does work. Condition good.