Two skateboarders are on the road with a window full of flags in the background.
Skateboarders are skating past a decorated window.
If the skateboarders are on the road, it is logical that they may be skating.  A window full of flags is certainly decorated - by flags.
exists p1 x1 x2 x6.(n_background(x6) & n_road(x2) & exists s1 x3 x4 x5.(on(x1,x2) & with(x2,x3) & of(s1,x5) & in(x5,x6) & n_flag(x5) & Theme(s1,x4) & a_full(s1) & (x3 = x4) & n_window(x3)) & n_skateboarder(x1) & card_eq_2(x1))
exists e1 e2 x1 x2.(past(e1,x2) & n_window(x2) & Theme(e2,x2) & v_decorate(e2) & Actor(e1,x1) & v_skate(e1) & n_skateboarder(x1))