Spectators looking on as an individual riding a four-wheeler at an event.
people are taking photos at an event.
Because people are at an event doesn't mean individual is riding a four-wheeler.
exists e1 x1 x2.(at(e1,x2) & n_event(x2) & r_on(e1) & all x3.(n_four-wheeler(x3) -> exists s1 x4.(as(e1,x4) & for(x4,x3) & n_riding(x4) & a_individual(s1) & Theme(s1,x4))) & Actor(e1,x1) & v_look(e1) & n_spectator(x1))
exists e1 x1 x2 x3.(at(e1,x3) & n_event(x3) & Theme(e1,x2) & Actor(e1,x1) & v_take(e1) & n_photo(x2) & n_people(x1))