1.Ne3 ! ~

2.N:g4 + (A)

2...Kd4 3.Bf6 # (C)

2...Kf4 3.Bd6 # (D)

2.Nc4 + (B) 

2...Kd4 3.Bf6 # (C)

2...Kf4 3.Bd6 # (D)

1...Bg3 2.Bf6 + (C)

2...Kf4 3.Ng2 #

2...K:f6 3.N:g4 # (A)

2...Kd6 3.Nc4 # (B)

1...Bc3 2.Bd6 + (D)

2...Kd4 3.Nc2 #

2...Kf6 3.N:g4 # (A)

2...K:d6 3.Nc4 # (B)

1...B:b4 2.R:b4 ~ 3.Re4 # 3.N:g4 #

The two thematic variations have the moves of the two threats in the reverse order.