A group of young children playing pillow fight on a bed.
The children are playing together.
Bed's are not longer than 8 feet normally.  Since the area is small in size.  It would be impossible to not hit another child on  bed with a pillow swung unintentionally.  Therefore the children must be playing together.
exists e1 s1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & of(x1,x2) & on(e1,x6) & n_bed(x6) & Theme(e1,x4) & Actor(e1,x3) & v_play(e1) & n_fight(x4) & of(x4,x5) & n_pillow(x5) & (x2 = x3) & n_child(x2) & a_young(s1) & Theme(s1,x2) & n_group(x1))
exists e1 s1 x1.(n_child(x1) & a_together(s1) & Manner(e1,s1) & Actor(e1,x1) & v_play(e1))