A great mechanical puzzle is one that is not only fun while attempting the solution. Before you solve it, it should be exciting. A good puzzle invites you to somehow open it or to solve it. During the time that you’re trying to solve the puzzle, you shouldn’t get irritated.
Everyone’s has different irritation level. You must have enough excitement to dare to solve any puzzle but not too much that could discourage you. Most people can do more than they think and a great puzzle will stretch what you think your limits are. Some puzzles may still take many more attempts to master after you’ve finally solved it once.
How was it made? How does it work? Does it look better on the desk or the coffee table? What kind of person could think up a thing like this?
It should delight you while you watch others try, in their own way, what you’ve already accomplished. By watching other people attempt to solve the same puzzle, you notice that there was more than one way to come to the same solution. Different people go about solutions in different ways. Watching others solve a puzzle you think you know well can provide new insights.
When choosing a puzzle for yourself or someone else, remember that a great puzzle will be fun before it is solved, while solving it, and after it has been solved.