Surfer leaning back on surfboard.
Surf rider beginning to enter a trick.
You could lean back without calling it a trick.
exists e1 s1 x1 x2.(ne_nam_surfer(x1) & on(e1,x2) & n_surfboard(x2) & a_back(s1) & Manner(e1,s1) & Actor(e1,x1) & v_lean(e1))
exists e1 p1 x1 x2.(Topic(e1,p1) & Actor(e1,x1) & v_begin(e1) & exists e2 x3.(Theme(e2,x3) & Actor(e2,x1) & v_enter(e2) & n_trick(x3)) & n_rider(x1) & (x1 = x2) & ne_nam_surf(x2))