The rider holds on as the horse rears onto his hind legs.
A rider on a horse.
A rider holding on as a horse rears is on a horse.
exists e2 e1 x1 x2 x3 x4 x5.(n_leg(x4) & of(x4,x5) & n_hind(x5) & of(x4,x2) & n_male(x2) & n_horse(x2) & n_rider(x1) & r_on(e1) & as(e1,x2) & onto(e2,x4) & Actor(e2,x3) & v_rear(e2) & (x2 = x3) & Actor(e1,x1) & v_hold(e1))
exists x1 x2.(a_topic(x1) & on(x1,x2) & n_horse(x2) & n_rider(x1))