Monthly Archives: July 2013

Matchsticks – divide into 2 equal halves

1) Divide into equal halves*
Matches - divide into 2 equal parts exercise



Add 2 matches to divide the figures into two halves of equal size.

This problem comes from Ed Pegg jr, who published it as one of many problems in his column in Japan Airlines inflight magazine, Skyward. I think it is a nice example of an a-symmetric problem. When we design something, e have a natural tendency to design something symmetric. Designing something a-symmetric somehow seems much more difficult.

You can check your solution here

Matchsticks – some classics

Here are 2 problems from Henry Dudeney:
1) New match problem**
Dudeney matchsticks 204 exercise
In the illustration eighteen matches are shown arranged so that they enclose two spaces, one just twice as large as the other. Can you rearrange them (1) so as to enclose two four-sided spaces, one exactly three times as large as the other, and (2) so as to enclose two five-sided spaces, one exactly three times as large as the other? All the eighteen matches must be fairly used in each case; the two spaces must be quite detached, and there must be no loose
ends or duplicated matches.

2) The six sheep-pens**
Dudeney matchsticks 205 exercise
Here is a new little puzzle with matches. It will be seen in the illustration that thirteen matches, representing a farmer’s hurdles, have been so placed that they enclose six sheep-pens all of the same size. Now, one of these hurdles was stolen, and the farmer wanted still to enclose six pens of equal size with the remaining twelve. How was he to do it? All the twelve matches must be fairly used, and there must be no duplicated matches or loose ends.

Both appeared in Dudeneys “Amusment in Mathematics”.

You can check your solution here and here

Review metal puzzles from TTIE and Eureka

This is one of three reviews to be published this summer while i’m away on holiday,

This post is about metal puzzles that I received for my birthday and fathersday. My thanks go to the family members who donated them.

The metal puzzles from T.T.I.E, PO Box 62 2420 AB The Netherlands are a series of sturdy metal puzzles. They come in grey boxes, which are mostly of a standard size.

SAM_0632 simple TTIE Many of the smaller ones look like standard problems, consisting of 1 twist. I was not able to find their website, zo it is probably not a very big firm.

SAM_0631 Three rings from Eureka! 3d puzzlesTwo of the puzzles I received are more original, they come from Eureka! 3D puzzles. The one with three rings is nice, I havent seen it before, though all the elements are very standard.

The puzzle which I christianed “Double E” is a nice one. It took it with me to the office, where my puzzle friends quickly solved it. Then I twisted them into each other again, and somehow we have been unable to separate them again.

You can find the website of the supplier at, though they only sell to retailers, and dont seem to sell to individuals.

Review crystal jigsaw puzzles

This is one of three reviews to be published this summer while I’m away on holiday,

This post is about plastic 3D jigsaw puzzles that I received for my birthday and fathersday. My thanks of course go to the family members who donated them.

Now I must confess that I dont like jigsaws puzzles. One reasons is they are way too common for my taste. Another reason is that they do not tax my brain enough: it needs diligent work, but not hard work.
But when it comes to 3D puzzles, the borderline becomes fuzzy. Ravensburg has published 3D jigsaw puzzles for I estimate over a decade. All pieces look like ordinary pieces, except they are thicker, so you can build walls and roofs with them.

On the other end of the 3d spectrum are the Japanese kumiki puzles, often beautifully made of wood, and representing several types of buildings, animals, fruit and other objects.


Somewhere in between are the plastic 3D jigsaw puzzles. I discovered them on the web, as produced by Kimzel Gmbh in Germany. They have a series of about 40 models. I ordered mine through Moenen and Mariken. This shop is in Dutch, and I can recommend their service, which was excellent.
If you live in the USA, you can order them from Amazon, where they are marketed by BePuzzled.

The number of pieces varies greatly. I have an apple of 13 pices, several of 46 pieces, and I have seen some of 90-100 pieces. Despite their name, they are not really crystal, but a sturdy plastic that looks like it. The copyright belongs to Beverley Enterprises Inc. & Jeruel Ind Co Ltd. The latter is a China based Toys and Puzzle producer, and the puzzles are produced in China. The pieces fit together really well. I guess the plastic does make them affordable, prices range from 3-20 euros.