1.Nf3 f6 2.Nc3 c6 3.e3

Black can play 3...e6 which transposes to 1.Nf3 f6 2.e3 e6 3.Nc3 c6.

If 3...d6, there is a transposition with the line 1.Nf3 f6 2.e3 d6 3.Nc3 c6. White can try 4.Bc4 e6 5.Nh4 d5 6.Bb3 f5 or 4.Nh4 Bf5 5.Bc4 d5.

Another line is 3...d5 4.Nb5 cxb5 5.Bb5+ Nc6 6.Ne5 Bg4 7.f3 (or 7.Qf3 e6 8.Qg3) 7...fxe5 8.fxg4 e6 (or 8...e5; 8...g6).