People on the beach look up to the sky to see a large heart written in the air by the contrail of a plane.
There are no people at the beach.
People are on the beach looking up at the sky. If there were no people on the beach then no one would be able to look up at what the plane wrote in the sky.
exists e1 p1 s1 x1 x2 x3 x4 x5 x8 x9.(n_contrail(x9) & n_air(x8) & n_sky(x5) & n_beach(x4) & n_beach(x2) & Topic(e1,p1) & exists e2 e3 s2 x6 x7 x10.(Theme(e3,x6) & Actor(e3,x1) & v_see(e3) & Actor(e2,x9) & of(x9,x10) & n_plane(x10) & in(e2,x8) & Theme(e2,x7) & v_write(e2) & (x6 = x7) & n_heart(x6) & a_large(s2) & Theme(s2,x6)) & a_up(s1) & Manner(e1,s1) & to(e1,x5) & Actor(e1,x3) & v_look(e1) & on(x3,x4) & n_people(x3) & on(x1,x2) & n_people(x1))
exists p1 x1 x3.(n_beach(x3) & -exists x2.((x1 = x2) & at(x2,x3) & n_people(x2)))