I’ve been given permission by Samclem to post a link to my website. So, in response to those who have requested, I’ll provide the link.
I don’t make bolts in bits of wood or put weird things in bottles, but I know the people who make these sorts of things and / or collect them and study them. I myself just make a range of folded playing cards, some of which have an ‘impossible’ or counter-intuitive flavour to them.
There are two types (folded / linked) and you can read about them, and see a gallery of designs, here:
Correct on the pie. With the coins, using five coins form a cross, i.e.: one coin in the center w/ 4 coins surrounding it at equal intervals, 12-3-6-9. Now place the sixth coin on top of the center coin.
I have eight Wow! cards in a display in our living room, way over here in Australia. They never fail to cause amazement. They are so beautiful as well as totally baffling.
Even non-puzzle geeks (sadly there are some such people) find them intriguing.
That could work. Point is to pay close attention to the parameters and don’t assume. Most people assume that “divide” implies equal segments, which of course, it does not. With the coins, they assume that you can’t count a coin twice and usually don’t think of stacking them. There are many puzzling situations that are similar, I suspect that Jessica Rabbit’s puzzle employs some of this self deception.
Back to the original object, I’d like to submit that the dent is made by a bench vise or C-clamp, which was used to grab the end piece while bending the whole object (after soaking or steaming). That would allow you to drill the center teeth and put in the bolt or pencil.