Two brown dogs play with one another in the field.
Two black dogs are playing with one another.
The subjects can either be brown or black, not both.
exists e1 s1 s2 x1 x2 x3.(n_field(x3) & in(e1,x3) & with(e1,x2) & n_thing(x2) & card_eq_1(x2) & a_another(s2) & Theme(s2,x2) & Actor(e1,x1) & v_play(e1) & n_dog(x1) & a_brown(s1) & Theme(s1,x1) & card_eq_2(x1))
exists e1 s1 s2 x1 x2.(with(e1,x2) & n_thing(x2) & card_eq_1(x2) & a_another(s2) & Theme(s2,x2) & Actor(e1,x1) & v_play(e1) & n_dog(x1) & a_black(s1) & Theme(s1,x1) & card_eq_2(x1))