int rled=13;
int yled=12;
int gled=27;

void setup() {
pinMode(rled, OUTPUT);
pinMode(yled, OUTPUT);
pinMode(gled, OUTPUT);
}

void loop() {
digitalWrite(rled, HIGH);
delay(1000);
digitalWrite(rled, LOW);
digitalWrite(yled, HIGH);
delay(500);
digitalWrite(yled, LOW);
digitalWrite(gled, HIGH);
delay(1000);
digitalWrite(gled, LOW);
}