People are stretching on yoga mats.
They stretched on bikes.
People can't stretch on yoga mats and bikes.
exists e1 x1 x2 x3.(on(e1,x2) & n_mat(x2) & of(x2,x3) & n_yoga(x3) & Actor(e1,x1) & v_stretch(e1) & n_people(x1))
exists e1 x1.(on(e1,x1) & n_bike(x1) & Actor(e1,x1) & v_stretch(e1) & n_thing(x1))