The pattern repeats. White can fork three Black pieces with Ne6+. The only difficulty is the pawn at f7 that guards the needed square. There are various things one can do about such problems. The most obvious is simply to capture the pawn if you can, so here it goes 1. Rxf7, RxR, and now the pawn has been replaced by a piece that can't protect the e6 square. True, White sacrificed a rook to the cause; but now Ne6+ wins the queen. And then after Black recaptures RxN, White picks up a pawn that has been left loose by the sequence: Qxg6. White ends up trading a knight and a rook for a queen and two pawns.

You might imagine that the g6 pawn could be protected by Black's king, which (on this theory) would have escaped the knight fork by moving to f6. But if Black does move his king there, White mates in three moves. It starts with Nc3-d5+. Black has no good replies; if he plays BxNd5, for example, White has Rf1+. This forces Black to play KxNe6. Now White replies e4xBd5#.

When you capture the f7 pawn at the beginning, you should not assume that your opponent necessarily has to recapture the way you would like. He might prefer to let the pawn go rather than play into your hands; it depends on the quality of his alternatives. Here Black has the option of replying to Rxf7+ with Kg8, which loses the pawn but also takes the king out of forking range. What happens next? Imagine the board with White’s rook on f7 and Black’s king on g8, and you should see that White then has an easy capture of a piece with RxN: the rook has protection from the knight on g5, and so cannot be recaptured by Black’s king.