There are three blocks, named AAA, BBB and CCC. A medium blue square is covered by block AAA. Block AAA contains a medium yellow square which touches this shape. Inside block AAA is block BBB. A medium blue square and a medium black square are in this block. North of the medium blue square there is the medium black square. Block BBB covers another medium black square. To the north of medium black square number two is the medium blue square. Block BBB contains block CCC. Block CCC has a medium black square which is north of a medium yellow square. Block CCC covers the medium yellow square.
Is a medium blue square within all blocks?