Young boy playing with rocks.
A boy is building a brick wall.
Rocks and bricks are different objects.
exists s1 x1 x2 x3.(a_topic(x1) & with(x1,x3) & n_rock(x3) & n_playing(x1) & of(x1,x2) & n_boy(x2) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_build(e1) & n_wall(x2) & of(x2,x3) & n_brick(x3) & n_boy(x1))