A person on a skateboard jumps in a curve on the sidewalk.
The person is on a bicycle.
A skateboard and a bicycle are different
exists e1 x1 x2 x3 x4.(n_sidewalk(x4) & in(e1,x3) & on(x3,x4) & n_curve(x3) & Actor(e1,x1) & v_jump(e1) & on(x1,x2) & n_skateboard(x2) & n_person(x1))
exists p1 x1.(n_person(x1) & exists x2.(on(x1,x2) & n_bicycle(x2)))