int Led1Blau = 12;
int Led2Rot = 13;

void setup() {
  // put your setup code here, to run once:
  pinMode(Led1Blau, OUTPUT);
  pinMode(Led2Rot, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(Led1Blau, HIGH);
  digitalWrite(Led2Rot, LOW);
  delay(500);
  digitalWrite(Led1Blau, LOW);
  digitalWrite(Led2Rot, HIGH);
  delay(500);
}