//define output 
#define red 4
#define yellow 7
#define green 12

void setup() {
  // put your setup code here, to run once:
  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(900);
  digitalWrite(red, HIGH);
  delay(900);
  digitalWrite(red, LOW);
  delay(900);
  digitalWrite(yellow, HIGH);
  delay(900);
  digitalWrite(yellow, LOW);
  delay(900);
  digitalWrite(green, HIGH);
  delay(900);
  digitalWrite(green, LOW);

}