void setup() {
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
}

void loop() {
  int min = 2;
  int max = 11;
  for(int i = max; i>=min; i--){
    digitalWrite(i, HIGH);
    delay(1000);
    digitalWrite(i, LOW);
  }
  for(int i = max; i>=min; i--){
    digitalWrite(i, HIGH);
    delay(500);
    digitalWrite(i, LOW);
  }
  for(int i = max; i>=min; i--){
    digitalWrite(i, HIGH);
    delay(250);
    digitalWrite(i, LOW);
  }
  for(int i = max; i>=min; i--){
    digitalWrite(i, HIGH);
    delay(100);
    digitalWrite(i, LOW);
  }
}