1 function room1 ()
 2     print("in room1")
 3     local move = io.read()
 4     if move == "south" then
 5        return room3()
 6     elseif move == "east" then
 7        return room2()
 8     else
 9        print("invalid move")
10        return room1()   -- stay in the same room
11     end
12 end
13  
14 function room2 ()
15     print("in room2")
16     local move = io.read()
17     if move == "south" then
18        return room4()
19     elseif move == "west" then
20        return room1()
21     else
22        print("invalid move")
23        return room2()
24     end
25 end
26  
27 function room3 ()
28     print("in room3")
29     local move = io.read()
30     if move == "north" then
31        return room1()
32     elseif move == "east" then
33        return room4()
34     else
35        print("invalid move")
36        return room3()
37     end
38 end
39  
40 function room4 ()
41 
42     print("in room4")
43     print("congratilations!")
44 end
45 
46 room1()