A graffiti artist is spray painting bricks.
Someone is making an outdoor mural.
The graffiti artist is spray painting bricks but the artist isn't necessarily making an outdoor mural.
exists p1 x1 x2.(exists s1 x3 x4.((x1 = x3) & Time(x3,x4) & n_brick(x4) & n_painting(x3) & a_spray(s1) & Theme(s1,x3)) & n_artist(x1) & of(x1,x2) & n_graffitus(x2))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_make(e1) & n_mural(x2) & a_outdoor(s1) & Theme(s1,x2) & n_person(x1))