A small boy playing with a wheel.
A small girl playing with a wheel.
either it is a small boy playing or it is small girl  and cannot be both
exists s1 x1 x2 x3.(a_topic(x1) & with(x1,x3) & n_wheel(x3) & n_playing(x1) & of(x1,x2) & n_boy(x2) & a_small(s1) & Theme(s1,x1))
exists s1 x1 x2 x3.(a_topic(x1) & with(x1,x3) & n_wheel(x3) & n_playing(x1) & of(x1,x2) & n_girl(x2) & a_small(s1) & Theme(s1,x1))