Four females stand on the tip of their toes while practicing ballet in front of a black backdrop.
four men are on the tips of their toes.
The four people cannot be men and women at the same time
exists e1 e2 s1 x1 x2 x3 x4 x5 x6.(n_toe(x3) & of(x3,x2) & n_thing(x2) & n_tip(x2) & while(e1,e2) & in(e2,x5) & of(x5,x6) & n_backdrop(x6) & a_black(s1) & Theme(s1,x6) & n_front(x5) & Theme(e2,x4) & Actor(e2,x1) & v_practice(e2) & n_ballet(x4) & on(e1,x2) & of(x2,x3) & Actor(e1,x1) & v_stand(e1) & n_female(x1) & card_eq_4(x1))
exists p1 x1 x2 x3.(n_toe(x3) & of(x3,x2) & n_thing(x2) & n_tip(x2) & on(x1,x2) & of(x2,x3) & n_man(x1) & card_eq_4(x1))