People are wearing bright colored costumes.
People in fancy dress going to a party
Bright costumes do not have to be fancy dress and can by worn for other reasons than going to a party.
exists e1 s1 s2 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_costume(x2) & a_colored(s2) & Theme(s2,x2) & a_bright(s1) & Theme(s1,x2) & n_people(x1))
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & to(e1,x4) & n_party(x4) & Actor(e1,x3) & v_go(e1) & (x1 = x3) & in(x1,x2) & n_dress(x2) & a_fancy(s1) & Theme(s1,x2) & n_people(x1))