A costume party in full swing.
Everyone at the party is in regular clothes.
Everyone is either in a costume or regular clothes at a party.
exists s1 s2 x1 x2.(a_topic(x1) & in(x1,x2) & n_swing(x2) & a_full(s2) & Theme(s2,x2) & n_party(x1) & a_costume(s1) & Theme(s1,x1))
exists x2.(n_party(x2) & all x1.(n_person(x1) -> exists p1.(exists s1 x3.(in(x1,x3) & n_clothes(x3) & a_regular(s1) & Theme(s1,x3)) & at(x1,x2))))