This is one of the random IQ test puzzles available here. I can not find a clue to this at all and this is sort of bugging me for some time now.
It could be some kind of paper folding or just rotations; I am not sure though.
Puzzling Stack Exchange is a question and answer site for those who create, solve, and study puzzles. It only takes a minute to sign up.Sign up to join this community
This is an
XOR operation, acting from left to right.
(There may be some pattern acting top to bottom, but I haven't spotted it)
If you 'add' the left and the middle squares, it works as an XOR to produce the right square. So if a line is present in both squares, or in neither, then it won't be in the right square.
Therefore the answer is: