A guy doing a grind over an edge in his skateboard.
A guy skateboards at a roller park.
could be skateboarding anywhere not just at a roller park
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & in(e1,x5) & n_skateboard(x5) & of(x5,x1) & n_male(x1) & over(e1,x4) & n_edge(x4) & Theme(e1,x3) & Actor(e1,x2) & v_do(e1) & n_grind(x3) & (x1 = x2) & n_guy(x1))
exists x1 x2 x3 x4.(a_topic(x1) & at(x1,x3) & n_park(x3) & of(x3,x4) & n_roller(x4) & Time(x1,x2) & n_skateboard(x2) & n_guy(x1))