The hiker is following a trail uphill.
The hiker is going down the hill.
A hiker cannot go uphill and down the hill the same time.
exists e1 x1 x2 x3.(n_hiker(x1) & Theme(e1,x2) & Actor(e1,x1) & v_follow(e1) & n_uphill(x2) & of(x2,x3) & n_trail(x3))
exists e1 s1 x1 x2.(n_hill(x2) & n_hiker(x1) & a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_go(e1))