There is a relation between the shapes in the top equation on the left side. If we apply such an equation to the bottom shapes, which one from the right choices can fill the question mark?
Source: Iranian Ph.D. entrance exam 2017
On the first row,
the RHS is the exclusive-or of the first image on the LHS rotated clockwise through a right angle, and the second image on the LHS rotated by 180 degrees. That is: if we rotate those images in those ways and overlay them, the RHS has ink just where exactly one of the LH images has ink.
If we do the same on the second row (it seems like we need to shift the LHS images a little, which makes me uneasy, but never mind) we get