Victor Aberman (USA)
 
#3 4+3

  1.Be6+? Kxe6 2.Qf7#

      1...Kc6 2.Bxc4 e4 3.Qc7#

    but 1...Ke4!

 

  1.Be2! threat

      1...c3 2.Qc7  ~ 3.Qc4#

              2...Ke4 /Kd4 3.Qxe5#

              2...Ke6 3.Qf7#

   I. 1...Kc6  2.Bxc4 e4 3.Qc7# (model mate №1)

  II. 1...e4 2.Qb6 c3 3.Qd6 #     (model mate №2)

              2...e3 3.Bf3 #

 III. 1...Ke4 2.Qc5 c3 3.Qxe5#  (model mate №3)

              2...Kf4/Kf5 3.Qxe5#

        1...Ke6 2.Qf7#

 

Model mates, flight giving key.

Variations I, II and III are similar to each other.