This is a tough heavy pieces middlegame nut to crack. Black has an enormous passed pawn on d4 supported by the rook on d8 and queen on a2. White has tripled (!) on the seventh rank and is ready to smash into the black king with Rxg7. Black wants to push the d-pawn and then promote it, preferably with a simultaneous check on the white king. White wants to take on g7, then take on h7 with check and hopefully checkmate the black king on g7 or h7. If you can solve this problem on a piece of paper in 15 minutes without moving any pieces on a chess board, then wow.