People in red hooded jackets on bikes ride in front of old buildings.
The people are in a gang.
People in red hooded jackets  need not refer to a gang, there may be a few people.
exists e1 s1 s2 s3 x1 x2 x3 x4 x5.(in(e1,x4) & of(x4,x5) & n_building(x5) & a_old(s3) & Theme(s3,x5) & n_front(x4) & Actor(e1,x1) & v_ride(e1) & in(x1,x2) & on(x2,x3) & n_bike(x3) & n_jacket(x2) & a_hooded(s2) & Theme(s2,x2) & a_red(s1) & Theme(s1,x2) & n_people(x1))
exists p1 x1.(n_people(x1) & exists x2.(in(x1,x2) & n_gang(x2)))