void setup() {
  pinMode(10, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(21, OUTPUT);
  digitalWrite(21, LOW);
}

void loop() {
  digitalWrite(21, HIGH);
  delay(1000);
  digitalWrite(10, HIGH);  
  delay(1000);                      
  digitalWrite(10, LOW);
  delay(5000);
  digitalWrite(8, HIGH);  
  digitalWrite(8, LOW);   
  delay(5000);
  digitalWrite(21, LOW);
  delay(10000);
}