The brown dog sniffs the back of a smaller black dog.
Two dogs are sniffing each other.
Just because a brown down sniffs a smaller dog doesn't mean the two dogs sniff each other.
exists e1 s1 s2 s3 x1 x2.(n_back(x2) & Theme(e1,x2) & Actor(e1,x1) & v_sniff(e1) & of(x2,x1) & n_dog(x1) & n_dog(x1) & a_black(s3) & Theme(s3,x1) & r_more(s2) & a_smaller(s2) & Theme(s2,x1) & a_brown(s1) & Theme(s1,x1))
exists x1.(all x2.(n_other(x2) -> exists e1.(Theme(e1,x2) & Actor(e1,x1) & v_sniff(e1))) & n_dog(x1) & card_eq_2(x1))