The Cross & Crown (C&C) puzzle you see here is not a modern puzzle design by any means, no, not at all. In fact, the C&C has its roots in a puzzle designed by Louis S. Burbank in 1913, which was patented by the US Patent Office.
The C&C was Dr Goetz Schwandtner's IPP34 Exchange Puzzle. It all started when Goetz had a chance to see and play with a very rare metal version of the original design belonging to puzzle collector Rob Stegman at IPP32. Goetz collaborated with another collector, Michel van Ipenburg and together, worked with IPP31 award winning designer Robrecht Louage to reproduce the version that we have today, making it available to puzzle enthusiasts.
The modern C&C is made of trespa, a strong and durable material widely associated with table surfaces. Metal would have been too expensive and impractical for production in large quantities. The puzzle is precision cut to tight tolerances but everything slides smoothly as intended. Quality of construction and finish is very good like in all of Robrecht's work.
The C&C is a N-ary puzzle. I still have little idea what this means but you can see examples of these and read more about it on Goetz's site. Like the original design, the C&C consists of a "cross" pivoting on a circular disc containing cut-outs. Both the cross and disc are "linked" by four rivets that can slide along each arm of the cross as well as along the channels of the cut-outs. The object is to move all the rivets through these zig-zag channels and reach a point at the end where the cross can be disengaged from the circular disc.
Like an N-ary puzzle, there is a kind of repeating pattern of moves (this aspect I know!); sort of a back-and-forth motion. I have played with several other n-ary puzzles such as the Lock 250, Alles Schiebung and Numlock and have solved them without help. Yet, for this C&C, despite spending a lot of time on it, I just could not get beyond a certain point and found myself keep getting stuck halfway. Perhaps I am way off-tangent on this one, but I am finding the C&C very difficult!
N-ary puzzles exist in all styles, shapes and sizes. The Chinese Rings is perhaps the early originator of such puzzles but it is binary rather than N-nary. The C&C is yet another example of a growing number of N-ary puzzles that have come to the market since Jean-Claude Constantin's 1250-move Kugellager a while back. For those keen to acquire a copy of C&C, you can contact Goetz via his puzzle site.
Puzzle Master of Canada and Mr Puzzle of Australia also retail different N-ary puzzles, as do Wil Strijbos.