People walk down a flight of stone steps in public.
People from a tour group walk down a flight of public steps that are made of stone.
The people aren't necessarily from a tour group just because they are walking down a flight of stone steps.
exists e1 s1 x1 x2 x3 x4 x5.(down(e1,x2) & of(x2,x3) & Theme(s1,x5) & a_public(s1) & (x3 = x5) & n_step(x3) & of(x3,x4) & n_stone(x4) & n_flight(x2) & Actor(e1,x1) & v_walk(e1) & n_people(x1))
exists e1 e2 s1 x1 x2 x3 x4 x5 x6 x7 x8.(a_topic(x1) & from(x1,x2) & down(e1,x5) & of(x5,x6) & of(e2,x8) & n_stone(x8) & Theme(e2,x7) & v_make(e2) & (x6 = x7) & n_step(x6) & a_public(s1) & Theme(s1,x6) & n_flight(x5) & Theme(e1,x4) & v_walk(e1) & (x2 = x4) & n_group(x2) & of(x2,x3) & n_tour(x3) & n_people(x1))