void setup() {
  // put your setup code here, to run once:
  for(int LED = 2; LED <= 10 ; LED++){
    pinMode(LED, OUTPUT);

  }
}

void loop() {
  // put your main code here, to run repeatedly:
  for(int LED = 2; LED <= 10 ; LED++){
    digitalWrite(LED, HIGH);
    delay(200);
    digitalWrite(LED, LOW);
  }
  for (int LED = 2; LED <= 10; LED++){
digitalWrite(LED, LOW);
delay(50);
}

  for (int LED = 10; LED >= 2; LED--){
digitalWrite(LED, HIGH);
delay(200);
digitalWrite (LED,  LOW);
}

  for (int LED = 2; LED <=10; LED++){
digitalWrite (LED, LOW);
delay(50);
  }
}