# Geo patterns – squares

1) Squares

Which code belongs at the question mark?
If you wish, you can peek at a hint

Old visitors of this blog may note a change. The previous posts appeared about once a month, a pretty long period. They also offered a historical background of a type of puzzle. This post contains just 1 puzzle. I hope to do more of this 1 puzzle posts – they are easier to digest for the casual reader, they are lighthearted, and offer diversion.

The elaborate posts providing an overview of a type of puzzle require me a lot of time; time i don’t always have: there’s not only the time to write up a puzzle and check the solution, there’s also the need to do a lot of research. At the moment I have an issue about train shunting puzzles in the final stages, and also one about the Japanese Tangram, though I still have to do all the editing on this last one. And I have ideas for several more, such as the “zebra puzzles” and truth / false puzzles associated with Boolean logic. i still regard these posts as a main content provider for this blog.
I.m.h.o. they offer a lot of material. They also provide something in mental exercise which single puzzles do not offer.

Usually our brains are not really at work. Well, of course they do work, even tapping with a finger requires a lot of cells in our brain to work. What I mean is that our brain cells do a lot of routine work. We use our memory, and act from routine. This also applies to “brain workers”, such as accountants, programmers and managers. We humans have a natural tendency to fall back in routine. Single puzzles, especially when they are of a new type, force our brains to find new ways. We often don’t have a method at hand to solve them. This makes puzzles of a new type especially hard nuts to crack. In real life, an accountant may face this challenge when for example faced with a tooling called XBRL. A programmer may face such a challenge when trying to make the step from COBOL programming to C++ on smart phones.
After solving a single new puzzle, we have found some new ways to solve a problem. But often we do not yet have a clear distinction between the puzzle and the way we solved it. A series of puzzles of the same type helps our brains to add new heuristics to our problem solving skills, in the sense that our brains add a new routine to its arsenal of heuristics. I’m not sure how this relates to

# Odd one out

1) Letters
A H I M N O V W X
Which letter is the odd one in this series? solution

2) Digits
0 3 6 7 8 9
Which digit does not belong in this series? solution

3) Numbers
3 4 7 13 20 33 53 86 139
Which number does not belong in this series? solution

4) Ells

Which L does not belong in this series? (solution)

5) Series
Which of the 4 series above is different from the rest? (solution)

# Futoshiki

Some cultures simply produce more puzzles than others. Puzzles are very popular in Japan, and Japan has produced more puzzle types than just Sudoko’s. Kaikuro’s are another Japanese invention, and the “newest” trend are Futoshikis, which are also called Hutosiki. I am not sure about the Japanese history, but the English newspaper The Guardian introduced it in Europe in 2006.

Futoshiki are Latin Squares, just as Sudoku’s. A handy size is 5×5. Every row and column contains the 5 digits 1-5 each exactly once. In addition, The > (greater than) and < (less than) are used to give relations between the numbers.

Here are three examples:
1)

 1 2 v 3 < 4 5 2 < 4 <

I feel you shouldn’t need the solution, but if you are not sure you can check it at 71

2)

 1 V V V 3 4 3 V > 4

Again you can check your solution at nr 21

3)

 1 4 > < V 4 5 4 3 <

This solution is at solution 61

You can expect more of these puzzles in one of our e-books