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

}

void loop() {
  // put your main code here, to run repeatedly:



for(i=2;i<=9;i++)
{
 digitalWrite(i, HIGH);  
      delay(250);
      digitalWrite(i, LOW);
}
  for(int i=8;i>2;i--)
  {
    digitalWrite(i, HIGH);  
      delay(250);
      digitalWrite(i, LOW);
      
  }

}