# Was given this question: what is the pattern?

I was given this as a quick challenge, but the underlying pattern behind it eludes me entirely. Can anyone suggest what the next image along might be (screenshot of correct answer) and explain HOW they reached this conclusion?

I feel like a moron for not recognising the pattern here.

• +1 I think some people aren't upvoting your question because they think the puzzle is poorly written. However, you're not presenting the puzzle for us to solve. You're presenting someone else's puzzle and asking for a canonical answer, which is definitely on-topic here. – Kevin Jan 24 '15 at 19:58

Assuming D is the answer (can't see dropbox at work),

the circle alternates moving one space and two spaces per turn going left and reversing when it runs out of room, and the x alternates moving 1 space and 0 spaces per turn going right.

• This is a terrible puzzle for an "IQ test". Solution A could be equally valid if the pattern of the circle is 1 left 2 left 1 right 2 right looping. – No. 7892142 Jan 23 '15 at 22:50
• Excellent point! – DevOfZot Jan 23 '15 at 23:01
• @No.7892142 right? I thought it seemed as though there were multiple solutions... – yellow-saint Jan 27 '15 at 9:36

The circle and x both move one space at a time. The circle is initially going towards the top left, and the x is going towards the bottom right. If the circle is going to collide with the x, then the circle jumps over the x, and the x stays in place. The circle will not jump the x if it is in a corner (perhaps because it can't get the proper footing in such a small space). If either shape hits a corner, they turn around and go the opposite direction.

• Or an alternate interpretation is that the circle alternates moving 1 space and 2 spaces, which leads to the same answer. – DevOfZot Jan 23 '15 at 22:03
• @DevOfZot I think you're right. My solution doesn't agree with the transition from step 3 to 4 anyway. – blakeoft Jan 23 '15 at 22:05
• Thanks, didn't notice that about step 3-4; I'll post it. – DevOfZot Jan 23 '15 at 22:07

The answer is "D" for the following reason:

1) There are 6 regions. Let's call the upper left region Region #1 and proceed southeast as Region #2, Region #3, Region #4, Region #5, Region #6.

2) The starting position is Box #1.

3) Looking only at the $+$ movements, we see that it appears to spend 2 turns in the same position. This is evidenced by Boxes #2, #3, #4, and #5.

4) $o$ is moving northwest as evidenced by the change of position from Box #1 to Box #2.

5) Whenever $o$ encounters $+$, it jumps over $+$ and when $o$ finally encounters the northwest corner it reverses direction.

6) In Box #5, the $+$ is completing its time in Region #3 and must now proceed to Region #4. $o$ must continue from Region #4 to Region #5 and continue until the corner where it will once again reverse direction.