#define R 27
#define Y 26
#define G 25
void setup() {
pinMode(R,OUTPUT);
pinMode(Y,OUTPUT);
pinMode(G,OUTPUT);
}
void loop() {
digitalWrite(R,LOW);
digitalWrite(Y,LOW);
digitalWrite(G,HIGH);
delay(3000);
digitalWrite(R,LOW);
digitalWrite(Y,HIGH);
digitalWrite(G,LOW);
delay(1000);
digitalWrite(R,HIGH);
digitalWrite(Y,LOW);
digitalWrite(G,LOW);
delay(2000); //ms = 1/1000sec
}