void setup() {
   Serial.begin(9600);
  for (int i = 2; i <= 13; i++)
  {
    pinMode(i, OUTPUT);
   
  }
}
void loop() {
  for (int i = 2; i <= 13; i++)
  {
    Serial.print("la lED ");
    Serial.print(i-1);
    Serial.println(" est alumée");
    digitalWrite(i, HIGH);
    delay(1000);
    digitalWrite(i, LOW);
  }
  for (int i = 12; i >= 2; i--)
  {
   Serial.print("la lED ");
    Serial.print(i-1);
    Serial.println(" est alumée");
    digitalWrite(i, HIGH);
    delay(1000);
    digitalWrite(i, LOW);
  }
}