Traffic Light String

When I was the pianist in another ward, the chorister made up one of these, only she used a 1 Liter pop bottle that she cut the middle out of, and fit the two ends together, to hold the string.  Apparently, there is no such thing as red, yellow, and green multi-colored yarn, so I bought three small yarn thingys(?) and tied them together randomly.

Not owning a liter of pop, I needed to make use of what could be found around the house.  Eventually I found a can of french-fried onion rings in my pantry,  put them in a zip-lock, punched a small hole in the lid, covered the can with wrapping paper, printed off some pics I found online, and voila'!

A helper pulls the string steadily while we sing.  Of course green="GO," Red="STOP," and then they'll hum when the yellow string surfaces.