本程序实现交通信号灯控制逻辑如下：开始为四个路口的红灯全部亮之后,东西路口的绿灯亮,南北路口的红灯亮,东西路口方向通车,延时一段时间后（20秒）,东西路口的绿灯,闪烁若干次后（3秒），东西路口的绿灯熄灭，同时东西路口的黄灯亮,延时一段时间后（2秒）,东西路口的红灯亮,南北路口的绿灯亮,南北路口方向通车,延时一段时间后（20秒）,南北路口的绿灯闪烁若干次后（3秒）,南北路口的绿灯熄灭, 同时南北路口的黄灯亮，延时一段时间后（2秒）,再切换到东西路口的绿灯亮,南北路口的红灯亮,之后重复以上过程。-The traffic signal control logic program as follows: begin after all four intersection of the red light, green light stuff intersection, the intersection of the north-south red light, what direction traffic intersection, delay some time (20 seconds), something intersection green light flashes several times (three seconds), crossing the green stuff off, while the bright yellow stuff intersection delay period of time (2 seconds), something intersection red light, green light junctions north and south, north and south intersection direction of traffic, the delay period of time (20 seconds), the junction of the north and south after the green light flashes several times (three seconds), the intersection of the north-south green light, yellow light while the north-south junction delay after a period of time (2 seconds), then switch to something crossing the green light, red light intersection north and south, then repeat the process