I found some sample Mensa IQ test questions at the Mensa Singapore website. There were 8 questions inside it. I managed to answer most of them without too much problem, however, I could not answer the last one. This is the question:
I could not figure out the pattern that governs which part in each square is shaded. The most that I could find out is that when the first four pictures are added(inclusive of overlapped parts), the last picture is produced, so the answer is D. However, I think that is wrong though, and even if it is really D, there is a way better explanation that explains why it is D. Any help in this puzzle is appreciated. Thank you.