# Word-list puzzle



## robert@fm (Mar 9, 2015)

Given the following word list:

AN, AS, ER, OR, NOT, PEN, SET, SOP, ...

1) What is the rationale behind this list?

2) What ninth word completes the list? (There are five possibilities that I can think of, the order of the letters doesn't matter.)

Clue:  Think in threes.


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## robert@fm (Sep 15, 2018)

Decided to bump this one as nobody got it. 

Another clue: think of magic squares.


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## mikeyB (Sep 17, 2018)

Think in threes? Magic squares? It’s 40 odd years since I took acid.


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## robert@fm (Sep 25, 2018)

I would have thought someone would have got this by now, given that the finished list is exactly nine words long, and the hint about magic squares.


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## robert@fm (Jan 14, 2019)

Nobody got this (and nobody got this on the other forum where I originally posted it), so I'll explain.

This list is part of a game whereby each of two players take turns to pick a word, and the first to get three words containing the same letter is the winner. 



Spoiler: This is your last chance to solve the puzzle yourself. Still not got it? Then click to open...



The game is, of course, a thinly disguised version of noughts and crosses.  Unlike the original version (which I think was called Jam or Hot), the nine words have been chosen to have the absolute minimum number of letters they need to contain, no extra "padding" letters. Having extra letters makes the list easier to devise, and makes the isomorphism with noughts and crosses less obvious, but to my mind is less aesthetically pleasing. 

The fourth word could thus be PART, PRAT, RAPT, TARP or TRAP; I don't know of any other possibilities.

And I finally(!) get to upload the explanatory image I created all those years ago, and which has been waiting for this day ever since. 


The magic-square connection is due to another game, in which the two players pick digits from 1 to 9, and the winner is the first to have three digits which add to 15; the 8 possible ways of selecting such digits correspond exactly to the 8 lines of a 3x3 magic square.


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