Someone walking along a wall.
A person is moving.
Someone is a person, walking is a way of moving, so a person is walking along a wall.
exists x1 x2.(a_topic(x1) & along(x1,x2) & n_wall(x2) & n_walking(x1))
exists e1 x1.(Actor(e1,x1) & v_move(e1) & n_person(x1))