Lock 250 / Schloss 250

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Name
Lock 250 / Schloss 250

Designer
Jean-Claude Constantin, one of the most prolific puzzle designers around. Too see his work, click here.

Manufacturer
Jean Claude Constantin. Available from Mr Puzzle of Australia, Sloyd of Finland and PuzzleMaster of Canada. My copy (together with some other puzzles) came from Sloyd, great service and very reasonable shipping rates.

Type & Classification
Puzzle lock. But also a puzzle within the category of "n-ary" puzzles. For more on "n-ary" puzzles, you can read puzzle collector Goetz Schwandtner's article here. For a super humongous lock that requires over 340 million moves, you can read Allard's post about the Generation Lock. 

Dimensions
9.9cm (Width) x 14.7cm (Height) and 3.2cm (Depth). A relatively large puzzle.

Materials & Construction
Plywood layers laser cut and glued together, with external veneer. Steel screws and sliders. Construction fit and finish is very good overall. However, the sliders don't slide as smoothly as they should when the internal wooden plates have moved into certain positions. Some moves ok, some not. Slight jamming occasionally, but nothing serious.

Overview
Not the usual trick lock in the traditional sense but rather a "n-ary" puzzle shaped like a giant pad-lock.

Object is to open the shackle and to do this, all the 4 sliders must be moved left and right to end up all on the left side. It takes 250 moves to open and hence a further 250 to close. Does take a while to just open the lock. The bottom slider is the main one that facilitates the moving of the other 3 sliders above it.

If you get the moves correct, its more an exercise in repetitive moves which eventually leads to the release of the shackle. But wrong moves can set you back a bit and you have to repeat any number of steps from 2 to 20.

I made some wrong moves and took longer than really necessary to solve this one.

Difficulty Level

Not difficult once you get going and discover the pattern of how the sliders operate, although the repetition may cause some very tired fingers. But the anticipation of solving does build up gradually as you see the topmost slider moving slowly towards the left, which signals the end is (finally) near.

Summary
The Lock 250 is a nice and different take on both the trick/puzzle lock as well as the n-ary puzzle. Great concept except my own copy has been let down a bit by the execution; ie the less than efficient sliding mechanism which make for some rather tiring (and frustrating) puzzling.