Comments on: impossible puzzle?

Question: impossible puzzle?

leibniz — Mon, 12 Dec 2005 12:57:33 -0800

I played this IQ test online a few days ago here: http://www.iqtest.dk/main.swf and didn't do too badly. However, the last question (no. 39) seems completely impossible. I worked out by elimination which answer must be the right one but I still can't figure out why it's right. Are there any genuises out there who can put me out of my misery please?

By: beautifulstuff

beautifulstuff — Mon, 12 Dec 2005 13:01:43 -0800

Can you summarize the question for us, so we don't have to take the whole test to find out what it is?

By: voidcontext

voidcontext — Mon, 12 Dec 2005 13:05:19 -0800

Yes, what beautifulstuff said. Flash sucks.

By: null terminated

null terminated — Mon, 12 Dec 2005 13:05:51 -0800

By: beautifulstuff

beautifulstuff — Mon, 12 Dec 2005 13:06:03 -0800

Oh never mind. I see you can skip to the last question without taking all the previous ones. And it's a graphical question, so it can't be easily described in text.

By: I Love Tacos

I Love Tacos — Mon, 12 Dec 2005 13:08:51 -0800

Here's a copy of the question:

By: smackfu

smackfu — Mon, 12 Dec 2005 13:09:32 -0800

Tic tac toe boards?

By: I Love Tacos

I Love Tacos — Mon, 12 Dec 2005 13:09:46 -0800

null terminated: great minds think alike, but yours thinks about 3 minutes earlier.

By: j.edwards

j.edwards — Mon, 12 Dec 2005 13:10:20 -0800

What's the correct answer? Is it C?

By: null terminated

null terminated — Mon, 12 Dec 2005 13:10:48 -0800

nah, I got a 5 minute head start.

By: andrew cooke

andrew cooke — Mon, 12 Dec 2005 13:26:52 -0800

well, i can justify A, but it seems pretty weak. all the "ok" examples are "jumbled up", and the only way i can find to describe that compared to the candidates is by counting the size and number of straight "chains" of the same shape. there are no straight chains of length 3 and a maximum of 3 chains of length 2 (allowing for the same piece being in more than one chain). only "A" is consistent with that....

By: andrew cooke

andrew cooke — Mon, 12 Dec 2005 13:28:34 -0800

i guess if you count a chain of 3 as being two chains of length 2 that overlap you might simplify that rule. still seems unconvincing to me.

By: alms

alms — Mon, 12 Dec 2005 13:46:00 -0800

I think the answer is F, because the correct answer can't have a chain of 3 of the same symbols, where symbols can chain on sides but not corners.

By: alms

alms — Mon, 12 Dec 2005 13:46:53 -0800

Nevermind, I see the answer I gave is not correct. Time to keep thinking...

By: mbd1mbd1

mbd1mbd1 — Mon, 12 Dec 2005 13:48:17 -0800

alms - a counterexample to that rule would be the lower center grid.

By: andrew cooke

andrew cooke — Mon, 12 Dec 2005 14:03:25 -0800

oh, my answer isn't quite right because f would apply too. i suspect you could bend it slightly to give a bent chanin of 3 a lower weight...

By: twiggy

twiggy — Mon, 12 Dec 2005 14:07:42 -0800

this is hurting my head. why did you have to post this? argh.

By: soma lkzx

soma lkzx — Mon, 12 Dec 2005 14:07:52 -0800

the first one in the 2nd column is the 3rd one in the top row rotated 90 degrees to the left. same with the first in the 3rd row and the last in the 2nd row. jus' sayin'.

By: lester

lester — Mon, 12 Dec 2005 14:08:29 -0800

I think the answer is H, based on the pattern of duplicate shapes within each row.

By: jdroth

jdroth — Mon, 12 Dec 2005 14:12:21 -0800

I'm not sure the answer is visual. Might it be numerical? What if each square represented a specific number, and the sums for each symbol were somehow important? Am I making this too difficult?

By: mr_roboto

mr_roboto — Mon, 12 Dec 2005 14:21:09 -0800

OK; I have an idea. Each grid is a map of the overall layout. There is a square in each grid that corresponds to that grid's position in the overall layout (for example, the center square in the central grid, or the upper-right square in the upper-right grid). Let's call this square the grid's self-referrential (SR) square. Now, let's look for a pattern in the SR squares:

Left to right, from the top, we have:
X O T
O T X
O T ?

There are two patterns that I can see here. In horizontal rows, no SR square symbol is repeated. In vertical columns, exactly one SR square symbol is repeated exactly once. Both of these patterns can be completed by selecting an answer with an X in its SR square (the lower right). This leaves us with A,B,C,D, and F.

That's all I have now. As well as referring to themselves, however, the grids might also be referring to each other in this manner. I'm trying to work it from that angle.

By: jdroth

jdroth — Mon, 12 Dec 2005 14:22:46 -0800

Based on some rudimentary mathematical parsing (that probably makes sense only in my brain), I've pared my choices down to E, F, and H. (Seems like a lot of think F is a possibility.)

By: sergeant sandwich

sergeant sandwich — Mon, 12 Dec 2005 14:26:15 -0800

i suspect repeated cyclic permutations, but i'm still working on it...

By: TimeFactor

TimeFactor — Mon, 12 Dec 2005 14:28:48 -0800

The answer is C. I narrowed it down to C and F in a way that I can't explain in any Earth language, and F is like so obvious so it has to be C.

By: TimeFactor

TimeFactor — Mon, 12 Dec 2005 14:32:33 -0800

Actually, I take that back. It's F. In your Earth language: none of the original 8 has a group of like shapes that can all be navigated solely by non-diagonal moves. F is the only candidate for which that's also true.

By: vacapinta

vacapinta — Mon, 12 Dec 2005 14:33:20 -0800

Its odd. I've honed in on C and cant let go. Now I'm trying to work backwards to see what my brain seems to like about that choice.

By: mr_roboto

mr_roboto — Mon, 12 Dec 2005 14:35:49 -0800

TimeFactor writes "In your Earth language: none of the original 8 has a group of like shapes that can all be navigated solely by non-diagonal moves."

The center grid in the bottom row has such a group of Xs.

By: TimeFactor

TimeFactor — Mon, 12 Dec 2005 14:37:08 -0800

OK, the answer's still F but not for the reason I gave (middle column, bottom row violates the rule I gave above). The reason: no corners of all one shape and all adjacent sides have all three shapes.

By: Ryvar

Ryvar — Mon, 12 Dec 2005 14:37:51 -0800

The answer is B and I will explain why:

In each row of boards each shape has one board where it occurs once in each column, and two in which it occurs twice in any given column.

In the first row of boards: in the first board Triangles occur once in each column, in the second board Xs occurs once in each column, in the third board Os occur once in each column.

In the second row of boards: first board is Xs, second board is Os, third board is Triangles.

In the third row of boards, first board is Os, second board is Triangles, third board is Xs.

I figured this out my second time through the test, and my score went up from 133 to 135 with all other answers left the same.

By: rocket88

rocket88 — Mon, 12 Dec 2005 14:47:01 -0800

I get B. Here is my reasoning:
Numbering the original patterns 1-2-3 in the top row, 4-5-6 in the second, and 7-8-9 in the third, we need to solve for #9. To get from 3 to 4, and 6 to 7, the patterns are rotated clockwise 90 degrees, as noted by soma lkzx above.
To get from 1 to 2, or 2 to 3, etc, shift all symbols to the right by one space (Anything shifted off the right end of the grid will move to the leftmost space in the next lower row. For the third row it will move the the leftmost space in the first row) At the same time change x's to o's, triangles to x's and o's to triangles.
The pattern matches in all cases and results in pattern B

By: TimeFactor

TimeFactor — Mon, 12 Dec 2005 14:47:53 -0800

It seems Ryvar has "the" answer (based on the different scores) but but F still is "an" answer (modified from my last comment to eliminate D as well):
1) no corners of one shape.
2) no rows or columns of one shape.
3) adjacent rows and columns must have all three shapes

By: mr_roboto

mr_roboto — Mon, 12 Dec 2005 14:48:50 -0800

Ryvar: How does your schema exclude answer A?

By: TimeFactor

TimeFactor — Mon, 12 Dec 2005 14:51:39 -0800

OK, those criteria apply to C as well. I'm going back to my home planet. The answer is B.

By: mr_roboto

mr_roboto — Mon, 12 Dec 2005 14:53:09 -0800

I think rocket88 has it. Tricky.

By: twiggy

twiggy — Mon, 12 Dec 2005 14:58:05 -0800

rocket88: you say that to get from 1-2, shift all symbols 1 space to the right... that doesn't sem to apply for 1-2..

X A O
A O A
X X O

shifted right =

O X A
O A O
A X X

but 2 is:

A O X
A X A
X O O ...

Am I not understanding your logic?

By: TimeFactor

TimeFactor — Mon, 12 Dec 2005 14:58:27 -0800

Yes. rocket88 gives the right explanation for why B is the right answer. Very nice.

By: TimeFactor

TimeFactor — Mon, 12 Dec 2005 15:00:25 -0800

twiggy: from rocket88's explanation: At the same time change x's to o's, triangles to x's and o's to triangles.

By: JeNeSaisQuoi

JeNeSaisQuoi — Mon, 12 Dec 2005 15:00:28 -0800

good job rocket88, now tell me the meaning of life.

By: Ryvar

Ryvar — Mon, 12 Dec 2005 15:04:16 -0800

I should have more fully explained my method, but it was, it turns out, wrong.

In my method I not only looked at the one shape which had one in each column of a given board, but made sure that both other shapes had two in an arbitrary column. This applies in all 8 'givens.' However, this rule does NOT hold true for D and F. Unfortunately, both A and B would be valid answers using my method.

The first time I went through the test I marked 'A' before I hadn't time to fully study the question. The second time I studied it, ignored 'A' because I'd used that answer last test, and therefore marked 'B' and noticed the higher score.

My bad, and rocket88 wins.

By: WestCoaster

WestCoaster — Mon, 12 Dec 2005 15:36:16 -0800

twiggy -

You did the shift-right per what rocket88 said to do, but not substitution/change:

change x's to o's, triangles to x's and o's to triangles

By: Rhomboid

Rhomboid — Mon, 12 Dec 2005 15:41:19 -0800

I wonder if this question was lifted from this.

By: neuron

neuron — Mon, 12 Dec 2005 16:15:05 -0800

My girlfriend can't understand why I won't do sudoku puzzles. I've tried to explain to her that I've done Avogadro's number of logic puzzles in my life and there is nothing for me to prove by doing another one. She says I need to exercise my mind, apparently failing to notice that my daily reading lately has consisted primarily of invertebrate paleontology, developmental molecular genetics, and astrophysics, or that I'm building a system to bounce radio signals off the moon.

By: caddis

caddis — Mon, 12 Dec 2005 18:06:42 -0800

You just had to know some smart fucker would be here to solve this. Kudos rocket88; that was a very complex pattern. Catching both the shifting and character changes was quite a trick.

By: leibniz

leibniz — Tue, 13 Dec 2005 14:54:55 -0800

thankyou so much rocket88, your answer is beautiful.