There are three blocks. We call them A, B and C. Block C is above B. Block A is above C. Block A contains a medium black square. Block B contains two medium yellow squares. This block also contains a medium black square. Below a medium blue square, the medium black square and medium yellow square number two is medium yellow square number one. Medium yellow square number one is touching the bottom edge of this block. Below the medium black square and the medium blue square there is medium yellow square number two. Block C has one medium yellow square.
Is there a black square which is above a medium square above all medium squares which are above a medium square?