Two people are on top of a cannon.
Two people are on a cannon and another person comes along.
No way to know that another person comes along.
exists p1 x1.(exists x2 x3.(on(x1,x2) & of(x2,x3) & n_cannon(x3) & n_top(x2)) & n_people(x1) & card_eq_2(x1))
exists e1 p1 p2 x1 x2 x3.(n_person(x2) & exists s1.(Theme(s1,x3) & a_along(s1)) & Topic(e1,p2) & Actor(e1,x3) & v_come(e1) & n_person(x3) & -(x3 = x2) & exists x4.(on(x1,x4) & n_cannon(x4)) & n_people(x1) & card_eq_2(x1))