模拟十字路*通灯的控制。初始状态为红灯全亮，5秒后变成状态A。状态A：东西通车，东西方向绿灯亮，南北红灯亮。5秒后东西绿灯灭，黄灯闪烁，2秒后转入状态B。状态B：N南北通车，南北方向绿灯亮，东西红灯亮。5秒后南北绿灯灭，黄灯闪烁，2秒后转入状态A。-Analog intersection traffic light control. The initial state of the whole red light, 5 seconds into a state of A. Status A: what the opening green light east-west direction, north-south red light. 5 seconds after the green light to destroy things, the yellow light flashes, 2 seconds later transferred to the state B. State B: N north-south traffic, north-south direction of green light, red light thing. 5 seconds after the green light to destroy the North-South, the yellow light flashes, 2 seconds later transferred to the state A.