A long time ago when I was young (and for me that is a LONG time ago) I was exposed to a noise making toy. Wasn't able to make it work, so lost interest rather quickly. Then, there came along a Crocodile Dundee movie where he took this "thing" and went up a hill to make a "telephone call" for reinforcements, waved it around in the air making a roaring sound. Thought nothing more of it than to notice he put a LOT of effort into spinning this thing around over his head to make a low frequency buzzing. Even more recently, Keith Gilbert's characters made a bull roarer that was used to good effect, or so we are lead to believe, in making certain elements of his population nervous. He did, at least, put a name to it, so I looked it up. I confess that I had some doubts about how effective a noise maker these things might be, but I have a bit of time on my hands, so curiosity won the day. Rather than a full scale prototype with extra time and effort that might be totally wasted, there came upon my work bench a proof of concept model, simply to convince me that the thing actually works. It does, but the proof of concept noise would be lost next to a quietly running chest freezer. A couple notes, then: -It takes only a modest amount of pretwisting the cord to get started, once running the twist will increase with time in use. -It takes muscle to get it to buzzing, even at this size and light weight. My shoulder was displeased, and the buzz wasn't very loud.. -If/when I make a full scale model, the twisted string will be replaced with something not twisted, like maybe braided twine or monofilament fishing line. Otherwise, the twist will be untwisted in one direction, then over twisted in the reversal. -Along with heavier wood (this one was carved out of the cheapest pine I had in the scrap pile) I might add some weight. First thinking would be a fishing sinker attached to the tip by a snap swivel. That way, getting the sinker spinning would not be needed. -I think, but do not know, that dramatically heavier will be better, both for the effort in spinning it up, and for additional noise. If you do a google search, you'll see more shapes and decorations than I would have ever imagined. Seems like these things have popped up over the millennia for more purposes than "long distance phone calls."