A Mom and a kid on the beach with sailboats in the background.
The child and his mother are building a sandcastle.
background doesn't always mean sandcastle.
exists s1 x1 x2 x3 x4 x5.(n_background(x5) & n_beach(x3) & a_topic(s1) & subset_of(x2,s1) & on(x2,x3) & with(x3,x4) & in(x4,x5) & n_sailboat(x4) & n_kid(x2) & subset_of(x1,s1) & n_mom(x1))
exists e1 x1 x2 x3 x4.(n_mother(x3) & of(x3,x2) & n_male(x2) & n_child(x2) & Theme(e1,x4) & Actor(e1,x1) & v_build(e1) & n_sandcastle(x4) & subset_of(x3,x1) & subset_of(x2,x1))