I had a interesting and funny (well at the beginning not so funny) experience. I have been upgrading my lighting equipment (lamps, flashes, tripods, umbrella...) with a "foldable circular reflector".
That thing comes folded in a small pouch (30cm diameter, approx one foot). You open the pouch take it out, and then suddenly the whole thing opens like a parachute, becomes 1m (3-4 feet) big with a relatively rigid metal circle around it. Perfect to be used as a reflector. Now comes the question: how do I get that thing back in the pouch ? I tried 20 times, pushing, pulling, squeezing, turning in all possible directions... nothing.
I surfed on the internet to discover that quite a lot of people have the same stupid experience. They don't tell you how to do that in the shop and there are no instructions in the pouch !
Now to keep it short, here is the way to do it: (as found on the internet)
take the reflector in both hands, with one
hand on either side of the reflector.
Turn your hands in opposite directions and the reflector will
eventually fold down
into concentric circles and will fit in the pouch. That's as simple as
that.
Just magic...
As a by-product, you can use this to entertain friends visiting you or even organize "contests" to solve the puzzle. Even if you show the solution, but without explaining anything, most people will not be able to do it. I couldn't imagine I would have so much fun with a photography accessory.
I have read nightmare stories about this on the internet... people who bought the bigger version, that won't even fit in their car when unfolded and totally uncapable of refolding it back...