Here the concept is similar but harder to see. White almost has a pawn fork with d5-d6, but the move attacks a queen and a pawn, an unsuitable target. If only the Black king were on e7 rather than d7; and in that fantasy lies the solution: draw the king onto e7 by attacking the pawn there that only the king protects. White plays Rxe7, Black replies KxR (if Black moves the king, White skewers the queen with RxQ), and now the pawn push d5-d6 wins the queen (the knight on c4 provides the protection the pawn needs to attack it).
Notice, by the way, that White does all this while threatened with b5xN. The usual lesson repeats: when under even an obvious threat, consider whether you can effectively go on the offensive with a check of your own.