There are three blocks. Lets call them A, B and C. Block A has one medium yellow square. Below block A we have block B with one medium blue square in it. A medium black square is touching the bottom edge of this block. This shape is below the medium blue square. Below block B there is block C which contains two medium yellow squares. Medium yellow square number one is touching the bottom edge of this block. It is below medium yellow square number two.
What is below the black object? a blue thing or a medium yellow square?
blue thing medium yellow square  both of them none of them