1...Rb7 2.Ke7+ Ka7 3.Qa1# ( model )
    2...Rb8 3.Q:b8# ( model )
1...R:c7 2.K:c7+ Ka7 3.Qa1# ( model )

 1.Ke7+?  1...Kb7!   1.Qh1+?  1...g2!

1.Qf6? zz.  1...g2!
1...Kb7 2.Qb6+ Ka8 3.Qb8#
1...Rb7 2.Qa6+ Ra7 3.Qc8#
1...R(a1-a5) 2.Qb6 R(b1-b5) 3.Qa6# ( 5x model )
/ 1...R:c7 2.K:c7    1...Ra6 2.Qa6# /

1.Qb2! threat 2.Qb8#
1...Rb7 2.Qg2! zz. Ka7 3.Qa2# ( model )
/ 1...R:c7 2.K:c7 /