That does n't look like mud on the horse rider.
The horse stands in the pasture eating grass.
There can only be the horse or the rider.
exists x1 x3 x4.(n_rider(x3) & of(x3,x4) & n_horse(x4) & n_thing(x1) & -exists e1 x2.(like(e1,x2) & on(x2,x3) & n_mud(x2) & Actor(e1,x1) & v_look(e1)))
exists e1 x1 x2 x3 x4.(n_grass(x2) & of(x2,x4) & n_eating(x4) & of(x2,x3) & n_pasture(x3) & n_horse(x1) & in(e1,x2) & Actor(e1,x1) & v_stand(e1))