That is one example; there are countless others. It is true that the knight can't operate from a long distance as a bishop or rook can, but then it has the advantage of not requiring open lines since it jumps to the squares it attacks rather than sliding to them. In the diagram to the left, where the squares the knight attacks are marked with white spots, the knight controls f5 and g6 and thus does some of the work a bishop would do if it were on d3. The knight also attacks g8, and so performs some of the work that might be done by a bishop on c4. It attacks g6 and g8, and with help from the pawn on g7 this allows the knight to fill some of the roles that might be played by a rook on the g-file. With the squares marked like this, you thus should be able to imagine ways that adding one or two other pieces might result in mate—perhaps a heavy piece on the h-file; or picture the g7 pawn moved to h7 and a White bishop on the long dark diagonal. These are the sorts of mating ideas we will be considering here.