A group of people hanging upside down on a roller coaster.
People stuck on a roller coaster.
a group of people upside down on a roller coaster doesn't mean they are stuck.
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & of(x1,x2) & r_upside(e1) & on(e1,x4) & n_coaster(x4) & of(x4,x5) & n_roller(x5) & r_down(e1) & Actor(e1,x3) & v_hang(e1) & (x2 = x3) & n_people(x2) & n_group(x1))
exists e1 x1 x2 x3.(on(e1,x2) & n_coaster(x2) & of(x2,x3) & n_roller(x3) & Actor(e1,x1) & v_stick(e1) & n_people(x1))