Lately I reviewed the mechanical puzzle HARMONY designed by Kirill Grebnev and Dmitry Pevnitskiy which was their IPP entry 2010. One year earlier, at IPP 2009, the same guys entered the competition with an original design called SPANNER (the same word exists in German language by the way but does mean something VERY different). This puzzle is available from Kirill’s website but I bought my copy from William Strijbos’ company Streetwise because they produced a much larger and heavier version than the original puzzle. Cost point is Euro 18.-.
As earlier mentioned we are speaking about an outstanding design idea because the puzzle is actually a huge 22mm wrench where both ends are linked with a chain and a big metal ring is caught between the spanner and the chain. Self-speaking your aim is to free the ring. Whilst in the first moment one would think that this is impossible to solve SPANNER is not a difficult puzzle and I could solve it in about 5 minutes. The difficult rating is therefore a moderate 3 out of 10.
This puzzle is again a purchase recommendation for every puzzle fan alone due to its novel design. In addition it is a lot of fun to bring it to a party and let others try their luck on it. I am quite sure that they will be stunned the first moment but will solve it sooner or later. You just have to take care or advise them that they do not use unnecessary force on the chain preventing it to break.