Traffic Light(Updating)

1) The simple traffic light in a two way road.
     So there are two traffic lights 1 and 2 and each has green 1 and red 0;
                                                T1    T2
                                        S0     0       0
                                        S1     1       0
                                        S2     0       1
   促使state转变的：
1）input （not clock）
2）next clock edge

Delay in the graph is the key in the problem. In this case, we can generate another input signal as input.


2) A more complex traffic light