Friday 5 October 2007

Five coins, five moves, five hours

Here's a little coin trick. Nothing tricky about it actually but, as I've found, once one is shown how the trick is done, it's very difficult to remember the solution.

Arrange five coins, as shown.

You now have five 'moves' in which to rearrange the coins as shown below.


Let me outline the rules of 'moves'.

Coins are moved two at a time. Coins don't have to be adjacent, but the spacing between the coins must remain throughout the move.

Coin orientation must remain, i.e. a swivel manoeuvre that turns coins through 180 degrees is not allowed.

During a move, the only coins that can be moved are the ones being touched directly. By this I mean one cannot use a coin to move another coin.

Hint: it may help you to think "over, under, over, under, over", it may not. Also bear in mind that having an incentive to complete the trick is generally proven to be a disadvantage.

The person who showed me this trick had to wait about five hours before I 'got it'. The first person I shared the trick with also took about five hours before they mastered it.

Good luck!

6 comments:

Rana said...
This comment has been removed by the author.
Rana said...

I didn't get your hint. But it only takes FOUR moves anyway?

Ann Cardus said...

The hint, whilst being a red herring, does help some.

Whilst under the affluence of incahol I believe I've seen this achieved in three moves, but I'm unable to replicate this.

Rana said...

OK, if you start like this
..ABABA......
1 move the two leftmost to the right
....ABAAB....
2 move the two leftmost to the right
......AABAB..
3 move the two leftmost to the left
....AA..BAB..
4 move the two rightmost into the gap
....AAABB....
Four moves. Too easy. Or have I missed something?

Ann Cardus said...

At this point I'm forced to tell you that the challenge is to achieve the trick in five moves.

Good luck.

Ann Cardus said...

I should explain that it's all about the remembering and I know you've seen a demonstration.