Set-play: 1.Qf4 nMO×e4+ 2.Kf5 nMOg3‡
          
1…Ka4 2.Qe7 nMA×d6+ 3.Kf6 nMAe8‡


Block of the neutral Locust by the white King;
Zilahi theme;

Reciprocal transformation of neutral batteries: 
Initial battery MOA/LO to MAO/LO and 
initial battery MAO/LO to MOA/LO
after reciprocal captures of their forward-pieces.

Bi-valve realized by the black Q:
line opening for the neutral Mao/Moa, 
line closing for the neutral Moa/Mao 
on the mating move.
Distant self-block by the black Q.

Pins of black Q by the neutral Mao/Moa.