A cowboy on the back of a galloping horse.
A cowboy is on the horse.
A cowboy is a person on the back of a galloping horse.
exists x1 x2 x3 x4.(n_back(x2) & a_topic(x1) & on(x1,x2) & of(x2,x3) & n_horse(x3) & of(x3,x4) & n_galloping(x4) & n_cowboy(x1))
exists p1 x1 x2.(n_horse(x2) & on(x1,x2) & n_cowboy(x1))