A person rides his bike over graffiti drawn on the ground.
A person walks on a city street.
if a person rides, he can't walk at the same time.
exists e2 e1 x1 x2 x3 x4 x5.(n_ground(x5) & Theme(e2,x2) & Actor(e2,x1) & v_ride(e2) & over(x2,x3) & on(e1,x5) & Theme(e1,x4) & v_draw(e1) & (x3 = x4) & n_graffitus(x3) & n_bike(x2) & of(x2,x1) & n_male(x1) & n_person(x1))
exists e1 x1 x2 x3.(on(e1,x2) & n_street(x2) & of(x2,x3) & n_city(x3) & Actor(e1,x1) & v_walk(e1) & n_person(x1))