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.