Lock 250 puzzle lock by Jean Claude Constantin

Designed by Jean Claude Constantin this puzzle is called Lock 250 because there are 250 moves to open... that means another 250 moves to close again. And that's only if you get them all correct!

The 4 steel sliders on the front move the internal wooden plates of the puzzles and which slider you can move depends on the position of the internal plates.  Sliding each one in turn in a particular sequence will unlock and solve the puzzle.

It may not look like it at first but actually, the Lock 250 is in the same family as the Chinese Ring puzzle and others classified as n-ary puzzles. Where the Chinese Ring puzzle is a binary puzzle, moves have 2 states, the Lock 250 has 5 states quinary puzzle.

Size: 98mm x 145mm x 30mm
The puzzle is made from laser-cut plywood and the outside is veneered. This is a natural wood product and so the exact tone of the wood does vary from puzzle to puzzle. I've included a couple of photos of different puzzles to give you an idea of the woods used.

No solution provided.  With 250 moves to make... that's 250 of the correct ones! ..... it's not really practical to print a paper solution.  How would you know if you were even at the start to begin following the steps?

To read an interesting review that compares this puzzle to its HUGE big brother "Generation Lock" go to Puzzling Times Blog.