Two people with dreadlocks.
Two people with shaved heads
People with dreadlocks can't have shaved heads.
exists x1 x2.(a_topic(x1) & with(x1,x2) & n_dreadlock(x2) & n_people(x1) & card_eq_2(x1))
exists s1 x1 x2.(a_topic(x1) & with(x1,x2) & n_head(x2) & a_shaved(s1) & Theme(s1,x2) & n_people(x1) & card_eq_2(x1))