There are three blocks, A, B and C. A medium blue square and one medium yellow square are in block A. Below the medium yellow square is the medium blue square. To the right of block A there is block B which has a medium black square. Below the medium black square is a medium blue square. Above block B there is block C. It has one medium blue square.
Which object is to the left of a medium blue square? the medium black square or the medium yellow square?
the medium black square  the medium yellow square  both of them none of them