A brick wall has colorful graffiti on it.
Teenagers have tagged a wall.
We don't know if it was teenagers or adults who did the graffiti.
exists e1 s1 x1 x2 x3.(on(e1,x1) & n_thing(x1) & Theme(e1,x3) & Actor(e1,x1) & v_have(e1) & n_graffitus(x3) & a_colorful(s1) & Theme(s1,x3) & n_wall(x1) & of(x1,x2) & n_brick(x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_tag(e1) & n_wall(x2) & n_teenager(x1))