People playing a game in the pool.
People are playing Marco Polo in the pool.
There are other games to play in a pool besides Marco Polo.
exists e1 x1 x2 x3 x4.(n_pool(x4) & a_topic(x1) & in(e1,x4) & Theme(e1,x3) & Actor(e1,x2) & v_play(e1) & n_game(x3) & (x1 = x2) & n_people(x1))
exists e1 x1 x2 x3 x4.(n_pool(x4) & ne_per_polo(x2) & (x2 = x3) & ne_per_marco(x3) & in(e1,x4) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_people(x1))