1		start(lights(red,red)).
2
3		trans(switch_tl_peds,lights(X,red),lights(NX,red)) :- switch_tl_peds(X,NX).
4		trans(switch_tl_cars,lights(red,Y),lights(red,NY)) :- switch_tl_cars(Y,NY).
5
6		prop(lights(X,_),'='(tl_peds,X)).
7		prop(lights(_,X),'='(tl_cars,X)).
8
9		switch_tl_peds(red,green).
10		switch_tl_peds(green,red).
11
12		switch_tl_cars(red,red_yellow).
13		switch_tl_cars(red_yellow,green).
14		switch_tl_cars(green,yellow).
15		switch_tl_cars(yellow,red).
16
17		prob_pragma_string('SCOPE','STATE_PROPERTY("tl_cars") = "red"').