void setup() {
  
  int LED= 4; 
  while(LED<14){
    pinMode(LED, OUTPUT);
    LED= LED+1; 
  }
}
void loop() {
  int LED = 4; 
  while(LED<14){
    digitalWrite(LED, HIGH);
    delay(50);
    digitalWrite(LED, LOW);
    delay(100);
    LED= LED+1;
  }
  int LED2=13;
  while(LED2>3){
    digitalWrite(LED2, HIGH);
    delay(50);
    digitalWrite(LED2, LOW);
    delay(100);
    LED2= LED2-1;
  }
}