A dog on a leash walks on the sidewalk while another dog follows.
Two dogs walking outside.
A dog and another dog are two dogs.  Two dogs are walking on the sidewalk and the sidewalk is outside.
exists e1 p1 x1 x2 x3.(n_sidewalk(x3) & exists e2 x4.(Actor(e2,x4) & v_follow(e2) & n_dog(x4) & -(x4 = x1)) & n_dog(x1) & n_dog(x1) & while(e1,p1) & on(e1,x3) & Actor(e1,x1) & v_walk(e1) & on(x1,x2) & n_leash(x2))
exists e1 s1 x1 x2.(a_topic(x1) & a_outside(s1) & Manner(e1,s1) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_dog(x1) & card_eq_2(x1))