int LED1 = 12;
int LED2 = 10;

void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
}

void loop() {
  digitalWrite(LED1, HIGH); //LED1 ON
  delay(500);
  digitalWrite(LED2, HIGH); //LED2 ON
  delay(500);
  digitalWrite(LED1, LOW); //LED1 OFF
  delay(1000);
  digitalWrite(LED2, LOW); //LED2 OFF
  delay(1000);
}