"Butterfly's Revenge" is one of my most favourite puzzles! It is also one of the most difficult puzzles I have so far. Maybe if I had had more experience with such puzzles like it, I would not have found it that hard. But it was one of my first wire and string puzzles and I had great difficulties in solving it.
The puzzle consists of a lot of wire parts, combined together in the shape of a butterfly. There is also a string in there, but unlike other wire and string puzzles, it is not taken apart from the rest of the puzzle. What needs to be removed is a handle. Personally, I am more afraid of puzzles which have handles to be separated than those that have strings to be taken apart.
The string in "Butterfly's Revenge" ends in two wire (or metal) rings, each half of the string has also a bead on it - one round and one flat - and to make things more interesting, there is also a small ring which keeps the two halves of the string. The string is attached to one of the rings on the butterfly and could move on it, but cannot be taken completely out of that ring or the whole butterfly. The handle then enters two of the rings on the butterfly, including the one which has the string attached to it, and the string passes through the handle. This complex structure introduces the start point of the puzzle. I cannot imagine who has come up with the idea of this puzzle and how, but they did a great job!
I could say that two main features are used in the solution of "Butterfly's Revenge". I was not familiar with neither of them, due to the lack of experience with wire and string puzzles. That is why I failed at finding the intended solution by myself. To my surprise, I managed to find the second part of the solution. Lacking the knowledge about the first part, I did something else and ruined all my further chances in mastering the butterfly. Later, when I saw the solution, I regretted cheating.
The solution for "Butterfly's Revenge" is so great! It works perfectly with no force. So, anyone who reaches a point of a bit of a force needed, know that this puzzle is like any other - it has to be solved smoothly, no resistance of the pieces required.
I quickly apprehended the solution, and although I cheated, this one became one of my most favourite puzzles. I would have my memory erased, so that I can have another go at finding the solution by myself and have satisfaction and even more fun.
With all said (or written), I give the following ratings for "Butterfly's Revenge":
Implementation: 5 (I don't give it 6, because, to be honest, it is not that beautiful of a puzzle; but everything was designed with a purpose, even though some parts are not actually used in the solution)
Finally, I would recommend "Butterfly's Revenge" only to experienced puzzle-solvers. You might be more lucky than me and might already know some of the easier puzzles which could help solve this one. You can check this puzzle on PuzzleMaster here.