Some of the trees on the side of the track are beginning to change color with the season.
The posts that run along the outside of the walk are purple.
Posts are not trees.
exists e1 p1 x1 x2 x3 x4 x6.(n_season(x6) & n_track(x4) & n_side(x3) & n_tree(x2) & Topic(e1,p1) & Actor(e1,x1) & v_begin(e1) & exists e2 x5.(with(e2,x6) & Theme(e2,x5) & Actor(e2,x1) & v_change(e2) & n_color(x5)) & of(x1,x2) & on(x2,x3) & of(x3,x4) & n_thing(x1))
exists e1 s1 x1 x2 x3 x4.(n_walk(x4) & n_outside(x3) & n_post(x1) & Theme(s1,x1) & a_purple(s1) & along(e1,x3) & of(x3,x4) & Actor(e1,x2) & v_run(e1) & (x1 = x2))