String Pipe

thingiverse

Older folks will recall these toys, but I've yet to see them on store shelves lately. Simple in design, this toy requires just one action: blow through the pipe and watch as the string zooms around, forming a neat loop. Prints without needing any support structures. To create a decorative element, thread a length of knitting yarn or wool through the pipe after printing, then shape it into a loop by splicing the ends together. If you're not skilled at splicing, a small amount of superglue makes for a secure join. A knot might be too bulky to pass smoothly through the pipe, but a well-placed glue drop should do the trick.