Put on your thinking cap – and most have all, have fun! Your time starts … NOW!
Spoiler alert: do not read any further unless you want the answer.
Solved in 45 minutes by Arrowman, who correctly identified it as a vintage kaleidoscope in which the foreground cogs turn the coloured wheels to produce the patterns.
I do not crop, enhance or post-edit my images in any way. Shot with a Pentax K100D, using a Siigma 18-125mm lens. F5.6, 1/45 sec, ISO 800, focal length 125mm.