The Knot Simple is another of Doug Engel's many interesting puzzle designs. I had reviewed his Great Collision in an earlier post. Measuring about 5cm x 5cm x 5cm, it consist of three interlocking U-shaped pieces. For an all-metal puzzle, it is really good value for money at only CS$9.99 from PuzzleMaster of Canada. My shipping charges to Singapore cost me twice as much :-(
The puzzle pieces are entirely made of (what I think) is brass and each piece has been coated (or anodised) a different colour; gold, silver and copper. Quality and fit and finish for the price is surprisingly pretty decent. Although I have to say that once you play with the puzzle, rub marks start to form on the shiny surfaces...but then again, what do you expect for CA$9.99?
The object of the Knot Simple is to take apart the three interlocking pieces. This is "knot" that difficult. I managed to separate the three quite quickly; mainly through trial and error, fiddling and pulling each piece here and there, trying to figure what works. Putting the puzzle back together was also pretty easy, since there are only three pieces to work with. While the top photo appears to show a tightly fit unit, this is not really the case. When the puzzle is picked up, there is a fair amount of free-play between the pieces, hence don't expect the dis-assembly to be smooth and precise like that of a burr.
You may think that all the three pieces look identical, but not so. There are actually minor differences in the shape of each piece upon closer inspection. This because there is really an intended sequence to disengaging the pieces, although I didn't really know this at the time of solving, since I was just trying to move whichever piece that could move. Later as I checked the accompanying solution, I saw the sequence of dis-assembly and re-assembly which was in accordance with the colour of the pieces.
PuzzleMaster rates it at level 7 but I think its more a 6. There also appears to be a disparity between the printed copy of the solution and the puzzle itself; the colours assigned to the pieces in the diagram of the solution do not match the actual pieces of the puzzle. Either the diagram was wrongly printed or the pieces were coated with the wrong colours; I think its easier to change the former (NB: To the folks at PuzzleMaster, please take note).