int rojo=12;
int amarillo=14;
int verde=27;

void setup(){

  pinMode(rojo, OUTPUT);
  pinMode(amarillo, OUTPUT);
  pinMode(verde, OUTPUT);
  pinMode(21, OUTPUT);
  pinMode(22, OUTPUT);
  pinMode(23, OUTPUT);
}

void loop(){
  
  digitalWrite(rojo, HIGH);
  digitalWrite(23, HIGH);
  delay(250);
  digitalWrite(rojo, LOW);
  digitalWrite(23, LOW);
  delay(250);

  digitalWrite(amarillo, HIGH);
  digitalWrite(22, HIGH);
  delay(250);
  digitalWrite(amarillo, LOW);
  digitalWrite(22, LOW);
  delay(250);

  //bloque verde1 con rojo2

  //bloque amarillos
}