We have three blocks. Lets call them A, B and C. Block A contains a medium yellow square. Then, we have block B. It has one medium black square. This block also contains one medium blue square. The medium blue square is below the medium black square. Finally, below block A we have block C. It is below block B. It has two medium blue squares. Below medium blue square number two is medium blue square number one.
Which object is above a medium blue square? the medium yellow square or the black thing?
the medium yellow square  the black thing both of them none of them