1.S4*b5? - 2.Bf6(A),e*f4(B)#

1...R*d6(a) 2.S*d6#

1...Rd4(b) 2.S*d4#

1...R*b5 2.Q*b5#

but

1...Rc5(c)!

1.Qb6? - 2.Bf6(A),e*f4(B)#

1...R*d4(b) 2.Q*d4#

1...Rc5(c) 2.Q*c5#

but

1...R*d6(a)!

1.Qa8! - 2.Qh8#

1...Rc5(c) 2.Qe4#

1...R*d6(a) 2.Bf6(A)#

1...R*d4(b) 2.e*f4(B)#

1...Be8 2.Sf3#

Double-Rudenko, sycle of defences (ab-bc-ca).