A man sitting on a ball hides his face from a small kid.
It is a father and a son.
The man does not have to be the or even a father to interact with the child and a small kid may not be a son.
exists e1 e2 s1 x1 x2 x3 x4 x5.(from(e2,x5) & n_kid(x5) & a_small(s1) & Theme(s1,x5) & Theme(e2,x4) & Actor(e2,x1) & v_hide(e2) & n_face(x4) & of(x4,x1) & n_male(x1) & on(e1,x3) & n_ball(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_man(x1))
exists p1 x1.(n_thing(x1) & exists x2 x3 x4.((x1 = x2) & subset_of(x4,x2) & n_son(x4) & subset_of(x3,x2) & n_father(x3)))