A skateboarder riding a rail.
A skateboarder rail slides a set of ten stairs.
riding a rail is the same thing as rail slides
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_ride(e1) & n_rail(x3) & (x1 = x2) & n_skateboarder(x1))
exists e1 x1 x2 x3 x4.(Theme(e1,x3) & Actor(e1,x1) & v_slide(e1) & of(x3,x4) & n_stair(x4) & card_eq_10(x4) & n_set(x3) & n_rail(x1) & of(x1,x2) & n_skateboarder(x2))