Update (Dec 19, 2014): Two new versions are available. They allow you to thread some twine through them! http://www.thingiverse.com/thing:601653 http://www.thingiverse.com/thing:601656 A whistle commonly used by Shepherd's for giving commands to dogs. These things require a bit of practice to use, but can be very loud and fun once you get the hang of them. Check instructions for further information on how to play it. *Only use the whistle if you're using non-toxic materials Update June 26, 2014: Louder and easier to play whistle has been uploaded I've also added a drawing to better explain how to use the whistle. *Update September 18, 2014: Uploaded gcode of improved whistle because current version of Repetier and Slic3r aren't working as well for it. How to use Shepherd's whistle: Here's a video of a guy who is very talented at playing this type of whistle: https://www.youtube.com/watch?v=Mv66viUCn1Y