const int L1 = 2;
const int L2 = 3;
const int L3 = 4;
const int L4 = 5;
const int L5 = 6;
const int L6 = 7;
const int L7 = 8;
const int L8 = 9;

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);
  digitalWrite(2, LOW);
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
  }

void loop() {
digitalWrite(2, HIGH);
delay(100);
digitalWrite(2,LOW);
digitalWrite(3, HIGH);
delay(100);
digitalWrite(3,LOW);
digitalWrite(4, HIGH);
delay(100);
digitalWrite(4,LOW);
digitalWrite(5, HIGH);
delay(100);
digitalWrite(5,LOW);
digitalWrite(6, HIGH);
delay(100);
digitalWrite(6,LOW);
digitalWrite(7, HIGH);
delay(100);
digitalWrite(7,LOW);
digitalWrite(8, HIGH);
delay(100);
digitalWrite(8,LOW);
digitalWrite(9, HIGH);
delay(100);
digitalWrite(9,LOW);
digitalWrite(9, HIGH);
delay(100);
digitalWrite(9,LOW);
digitalWrite(8, HIGH);
delay(100);
digitalWrite(8,LOW);
digitalWrite(7, HIGH);
delay(100);
digitalWrite(7,LOW);
digitalWrite(6, HIGH);
delay(100);
digitalWrite(6,LOW);
digitalWrite(5, HIGH);
delay(100);
digitalWrite(5,LOW);
digitalWrite(4, HIGH);
delay(100);
digitalWrite(4,LOW);
digitalWrite(3, HIGH);
delay(100);
digitalWrite(3,LOW);
digitalWrite(2, HIGH);
delay(100);
digitalWrite(2,LOW);
}