void setup() {
  // put your setup code here, to run once:
 pinMode(8, OUTPUT);
 pinMode(10, OUTPUT);
 pinMode(12,OUTPUT);
}
void loop() {
  digitalWrite(8,LOW);
  digitalWrite(10, LOW);
  digitalWrite(12, HIGH);
  delay(1000);

  digitalWrite(10, HIGH);
  digitalWrite(12, LOW);
  delay(1000);
  
   digitalWrite(8,HIGH);
  digitalWrite(10, LOW);
  delay(1000); 
}