Which shape?

June 14, 2013 2:20 AM

What's the best response to this challenge?
posted by disillusioned to Grab Bag (15 answers total)

I'll say "D." The two shapes move this way: Left Shape moves counterclockwise one clock position (ie, from 1 o'clock to 12 o'clock) for two steps then flips top to bottom. Right Shape moves clockwise one clock position three times.
posted by taz at 2:39 AM on June 14, 2013 [4 favorites]

(This is my guess, by the way; I don't have any information about the actual answer.)
posted by taz at 2:40 AM on June 14, 2013

D. Left-hand shape rotates anticlockwise 45 degrees from first column to second column. Right-hand shape rotates clockwise 45 degrees from first column to second column.

From second to third column, left-hand shape is reflected along its long axis, and the right-hand shape is again rotated clockwise 45 degrees.

(On preview, same answer as taz)
posted by pipeski at 2:41 AM on June 14, 2013 [1 favorite]

Yep D fits the pattern horizontally and vertically
posted by BenPens at 2:54 AM on June 14, 2013 [1 favorite]

D'accord.
posted by seanmpuckett at 3:22 AM on June 14, 2013

hal_c_on, 'A' would mean a -90 degree rotation going from the 1st to 2nd columns. The rotation in rows 1 and 3 is -45 degrees. I hope this counts as 'answering the question' in the sense of clarifying why 'A' is not the solution.
posted by pipeski at 3:35 AM on June 14, 2013

D.

Fwiw, this is called "matrix reasoning" and appears on most IQ tests. Many psych labs use it to estimate full-scale IQ when giving the full test would be impractical.
posted by supercres at 5:38 AM on June 14, 2013

I got D with the same reasoning as taz. (I love these.)
posted by corvine at 6:38 AM on June 14, 2013

Another vote for D here.
posted by The Michael The at 7:05 AM on June 14, 2013

Yes, D. Use your hands or draw the shapes on pieces of paper and rotate them and you can see the sequence of how they change position quite easily.
posted by oneirodynia at 8:13 AM on June 14, 2013

This looks like a standard matrix reasoning puzzle but isn't, which is perhaps why the OP asked the question. This puzzle has two patterns (one for each shape) that run across the rows, with no relationship down columns. Matrix reasoning usually has one pattern across the rows and a different pattern down the columns.
posted by drdanger at 8:20 AM on June 14, 2013

Oops, ignore that, I am confused this morning!
posted by drdanger at 8:26 AM on June 14, 2013

This looks like a standard matrix reasoning puzzle but isn't, which is perhaps why the OP asked the question. This puzzle has two patterns (one for each shape) that run across the rows, with no relationship down columns.

Ah, don't be so quick! I agree with D, but can explain it in a different way (which ultimately works out to be the same) that incorporates columns: the left trapezoid rotates 45° counterclockwise as you move down each column; the right trapezoid rotates 45° clockwise as you move across each row.

Or, diagramatically (numbers indicate rotation by degrees; by convention a positive number indicates clockwise rotation and a negative number counterclockwise. Of course, 180=-180.):

Left trapezoid:

+--+  -45 +--+  180 +--+
|  | ---> |  | ---> |  |
+--+      +--+      +--+
 |         |         |
 |?        |-45      |-45
 v         v         v
+--+  ?   +--+  180 +--+
|  | ---> |  | ---> |  |
+--+      +--+      +--+
 |         |         |
 |?        |-45      |-45
 v         v         v
+--+  -45 +--+  180 +--+
|  | ---> |  | ---> |  |
+--+      +--+      +--+

Right trapezoid:

+--+  45  +--+  45  +--+
|  | ---> |  | ---> |  |
+--+      +--+      +--+
 |         |         |
 |?        |180      |180
 v         v         v
+--+  ?   +--+  45  +--+
|  | ---> |  | ---> |  |
+--+      +--+      +--+
 |         |         |
 |?        |-90      |-90
 v         v         v
+--+  45  +--+  45  +--+
|  | ---> |  | ---> |  |
+--+      +--+      +--+

That is, the matrix "math" works out for both trapezoids going either across or down, but it's easier to see going down for the left trapezoid, but going across for the right trapezoid.
posted by DevilsAdvocate at 11:21 AM on June 14, 2013 [1 favorite]

I think it's just the 45 degrees, left piece=top to bottom / right piece=left to right.

The 180 for each going in the other directions doesn't seem as natural, and is just the result of everything turning in 45 degree increments.

The trick seems to be that you're not sure if the patterns go by rows or columns, and it turns out the two pieces are actually independent and go in different directions.
posted by TheSecretDecoderRing at 8:29 PM on June 14, 2013

hal_c_on, I picked A, too, and I even did the hand thing first.
posted by Room 641-A at 4:04 PM on June 15, 2013