Mate in 3

1.Qb4 threat 2.Bf4+ Kxf4 3.Qxd4.
1...Bxf5 2.Ra4 threat 3.Qxd4;
1...exf5 2.Qb5 threat 3.Qxd5; 2...Ke6 3.Qe8;
1...Rxf5 2.Ba3 threat 3.Qxd6; 2...Kf4 3.Qxd4; 2...d3 3.Qe4 or 3.Bb2;
1...fxg2 2.Qd2 threats 3.Qxe2 and 3.Qf4.
Doubling on four different lines, with rear support provided in two variations, and the queen twice moving in front of the supporting piece. Extra unity is provided by the three defences on the same square.

Satanick Mukhuty: Nice doubling of pieces in the four variations. I would have probably missed 1...fxg2 without the hint.