int red1 = 10; int 
yellow1 = 9; 
int green1 = 8; 
// Traffic light two 
int red2 = 13; int 
yellow2 = 12; 
int green2 = 11; 
void setup () {  
//Traffic light one 
pinMode (red1, OUTPUT); pinMode 
(yellow1, OUTPUT); 
pinMode (green1, OUTPUT); 
// Traffic light two 
pinMode (red2, OUTPUT); pinMode 
(yellow2, OUTPUT); 
pinMode (green2, OUTPUT); 
} void loop () { 
changeLights (); 
delay(10000); 
} 
void changeLights () {  
//Both yellow lights turns on 
digitalWrite(green1, LOW); 
digitalWrite(yellow1, HIGH); 
digitalWrite(yellow2, HIGH); 
delay (7000); 
// turns off both yellow and turns on red1 and green2 
digitalWrite(yellow1, LOW); digitalWrite(red1, 
HIGH); digitalWrite(yellow2, LOW); 
digitalWrite(red2, LOW); digitalWrite(green2, 
HIGH); delay(7000); 
// both of the yellow lights turns on 
digitalWrite(yellow1, HIGH); 
digitalWrite(yellow2, HIGH); 
digitalWrite(green2, LOW); 
delay(3000); 
// turns off both yellow light and turns on grren1 and red2 
digitalWrite(green1, HIGH); digitalWrite(yellow1, 
LOW); digitalWrite(red1, LOW); digitalWrite(yellow2, 
LOW); digitalWrite(red2, HIGH); delay(7000); 
}