A BMX biker in a white and blue helmet rides in front of some blue and black boxes.
The biker is riding in a course.
Just because a biker is riding does not mean that he is riding in a course.
exists s1 s2 s3 s4 x1 x2 x3 x4 x5 x6.(a_topic(x1) & in(x1,x3) & in(x3,x5) & of(x5,x6) & n_box(x6) & a_black(s4) & Theme(s4,x6) & a_blue(s3) & Theme(s3,x6) & n_front(x5) & n_ride(x3) & of(x3,x4) & n_helmet(x4) & a_blue(s2) & Theme(s2,x3) & a_white(s1) & Theme(s1,x3) & n_biker(x1) & (x1 = x2) & ne_org_bmx(x2))
exists e1 x1 x2.(n_biker(x1) & in(e1,x2) & n_course(x2) & Actor(e1,x1) & v_ride(e1))