int l1=13;
int l2=12;
int l3=11;
int l4=10;
int l5=9;
int l6=8;
int l7=7;
int l8=6;
int l9=5;
int l10=4;

void setup() {
  // put your setup code here, to run once:
pinMode(l1,OUTPUT);
pinMode(l2,OUTPUT);
pinMode(l3,OUTPUT);
pinMode(l4,OUTPUT);
pinMode(l5,OUTPUT);
pinMode(l6,OUTPUT);
pinMode(l7,OUTPUT);
Serial.begin(9600);
}

void loop() {
digitalWrite(l1, HIGH);
digitalWrite(l10, HIGH);
digitalWrite(l1, LOW);
digitalWrite(l10, LOW);
delay(100);
digitalWrite(l2, HIGH);
digitalWrite(l9, HIGH);
digitalWrite(l2, LOW);
digitalWrite(l9, LOW);
delay(100);
digitalWrite(l3, HIGH);
digitalWrite(l8, HIGH);
digitalWrite(l3, LOW);
digitalWrite(l8, LOW);
delay(100);
digitalWrite(l4, HIGH);
digitalWrite(l7, HIGH);
digitalWrite(l4, LOW);
digitalWrite(l7, LOW);
delay(100);
digitalWrite(l5, HIGH);
digitalWrite(l6, HIGH);
digitalWrite(l5, LOW);
digitalWrite(l6, LOW);
delay(100);
digitalWrite(l6, HIGH);
digitalWrite(l5, HIGH);
digitalWrite(l6, LOW);
digitalWrite(l5, LOW);
delay(100);
digitalWrite(l7, HIGH);
digitalWrite(l4, HIGH);
digitalWrite(l7, LOW);
digitalWrite(l4, LOW);
delay(100);
digitalWrite(l8, HIGH);
digitalWrite(l3, HIGH);
digitalWrite(l8, LOW);
digitalWrite(l3, LOW);
delay(100);
digitalWrite(l9, HIGH);
digitalWrite(l2, HIGH);
digitalWrite(l9, LOW);
digitalWrite(l2, LOW);
delay(100);
}