There are three blocks. Lets call them A, B and C. There is one medium yellow square in block A. This block also has one medium blue square. The medium blue square is below the medium yellow square. Below block A we have block B which has one medium yellow square and one medium black square. The medium yellow square is below the medium black square. To the right of block B there is block C with a medium black square in it.
Which object is below a medium black square? the medium yellow square that is in block A or the medium yellow square that is in block B?
the medium yellow square  that is in block A the medium yellow square  that is in block B both of them none of them