h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Imagine a small plastic square, split up into a 4 by 4 grid of smaller plastic squares - 15 numbered squares and a space, allowing the plastic squares to be slid from side to side to change the pattern. The aim was to create patterns of numbers (or just a pattern).

Anybody know what they're called, or where to find them?

I haven't a clue what it might be called, besides, "Sliding Puzzle" or the like. You might find them at a party supply store, as I usually see them given out as party favors for little kids. They also appear as Halloween treats.

Those things are fun if you can solve them in front of people who can't. I call it the "Rubik's Cube Effect." It makes people think you're a lot smarter than you really are.

Wampus

A good trick is to have one of those with 'rate your mind pal' instead of numbers...

Then you can scramble it up and make it virtually impossible to solve

Well I tried googling on 'sliding puzzle' and found online versions of them - that's a start. Good going, Wampus!

I've yet to find anybody online stocking real ones yet - it's actually my sister who wants one - this could give her an idea for real life shops - neither of us thought of party shops.

I'm inclined towards places that stock traditional children's toys, but that tends to mean wooden yo-yos and whips and tops and such.

I don't think she'd appreciate one with 'rate your mind pal'

Well... anything will do, really... what you need is something with a repeated symbol...

I used to struggle with getting the numbers 1 to 15 in order. You are talking to somebody who 'solved' his Rubik cube by pulling it apart and reassembling it! I'm easily confused.

Ah, well -- it's a trick, really.

As it turns out, from any one position on such a game, you can get to exactly *half* of the other positions... any, in fact, which requires an even number of swaps of tiles to get to.

So if you make just one swap, it's unsolvable without swapping them back...

But if they have the same symbol, why swap them back?

Buy up a mountain of differnet Xmas Crackers and you'll get one, but don't come anywhere near here with the jokes puhlease.

Now I'm confused. I knew that would happen. I shall have to go and have a lie down in a darkened room.

And I'm a bit upset that my best source of classy jokes has been discovered.

Have you tried online auction places like ebay? They can be a pretty good source of unusual stuff. Or there's Hawkin's Bazaar (they have shops and are online) - they do all sorts of unusual stuff, but I don't know about sliding puzzles.

I just found this on ebay.co.uk:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=1920266267

It's not cheap, but it is a set of 7 'sliding tile puzzles', albeit old ones. You'll have to hurry if you want it, though, as there's only 7 hours left to bid.

The 4x4 sliding puzzle was originally called "The 15 Puzzle" but it is unlikely that anyone remembers this name now. The original one was invented by Sam Loyd. It had the numbers 1 - 15 but the 14 and 15 were the wrong way around. There was a huge prize for a method of getting them in order, but the puzzle was actually impossible.

If you get one that says "RATE YOUR MIND PAL", a good trick is to solve it, then rearrange it so that the first two letter are the original R and the other A, the one from PAL. Then give it to your friend to solve. He will assume that both the R and A are in the rate places and will continue from there. In this state, it is not solvable. You can solve it by swapping the A's around.

The Gnomon effect strikes again:

I don't believe any one person can know this much. I think Gnomon's actually a Government think tank

hmm....

Government's
National
Office for the
Ministry of
Obscure
(k)Nowledge

Enquiring Minds want to know....

Actually 'gnomon' comes from the Greek, where it means "the one that knows, interpreter, the one that shows the way".

Where I would buy one of those puzzles is in an Art and Hobby shop. In Dublin, these tend to have a lot of jigsaws and puzzles for adults, such as wooden blocks that have to be assembled into strange shapes. You might find a 15 sliding puzzle there. I've also seen much bigger ones such as 6 x 6 with pictures on them.

All the best acronyms are based on an appropriate word....

Like one of the computer systems Police forces use when they have large enquiries: The Home Office Large Major Enquiries System.

For which the acronym is... err... elementry.


Geggs

You can get the 'Fifteen Puzzle' from Brainwaves (£9.99 in their mail order catalogue. www.brainwaves.co.uk

Alternatively, get it from Hawkin's Bazaar ( http://www.hawkin.com ) for 99p!

Further research shows that Sam Loyd did not in fact invent the 15 puzzle. He popularised it. His version was called the 14-15 puzzle and had the 14 and 15 reversed, making it impossible. He offered a prize of $1000 for a solution, and drove the world mad. This happened in the 1870s, but there exist "15 puzzles" by other manufacturers from 1865 suggesting that Loyd borrowed the idea.