Put on your thinking caps, but most of all, have fun! You can have as many guesses as you want.
Your time starts …. NOW!
Spoiler alert: do not read any further unless you want the answer revealed.
Solved by Linda Bianic, who becomes the first person ever to solve three of these visual puzzles in a row. The object in the photograph is the hard plastic case that holds one or more cymbals of varying circumference. The bolt goes through the centre of the cymbals and holds them securely in place.
I do not crop, enhance or post-edit my images in any way. Shot with a Pentax K100D, using a Sigma 18-125mm lens. F5.6, 1/10 sec, ISO 800, focal length 88mm.
Featured in COMPLEX SIMPLICITY OF ART, March 2010.