Four people sitting in branches on a tree.
Two boys and two girls sit on the branches of a tree.
Any group of people can be sitting in the tree, we don't know that it was two boys and two girls.
exists e1 x1 x2 x3 x4.(a_topic(x1) & on(e1,x4) & n_tree(x4) & in(e1,x3) & n_branch(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_people(x1) & card_eq_4(x1))
exists e1 x1 x2 x3 x4 x5.(n_branch(x4) & on(e1,x4) & of(x4,x5) & n_tree(x5) & Actor(e1,x1) & v_sit(e1) & n_girl(x3) & card_eq_2(x3) & n_boy(x2) & subset_of(x3,x1) & subset_of(x2,x1) & card_eq_2(x1))