int dt=100;
void setup() {
pinMode(2, OUTPUT);// put your setup code here, to run once:
pinMode(3, OUTPUT);  
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);  
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);  
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);  
}

void loop() {
  digitalWrite(2,1);
  delay(dt);// put your main code here, to run repeatedly:
  digitalWrite(3,1);
  delay(dt);
    digitalWrite(4,1);
  delay(dt);
    digitalWrite(5,1);
  delay(dt);
    digitalWrite(6,1);
  delay(dt);
    digitalWrite(7,1);
  delay(dt);
    digitalWrite(8,1);
  delay(dt);
    digitalWrite(9,1);
  delay(dt);
    digitalWrite(9,0);
  delay(dt);
   digitalWrite(8,0);
  delay(dt);
   digitalWrite(7,0);
  delay(dt);
   digitalWrite(6,0);
  delay(dt);
   digitalWrite(5,0);
  delay(dt);
   digitalWrite(4,0);
  delay(dt);
   digitalWrite(3,0);
  delay(dt);
   digitalWrite(2,0);
  delay(dt);
}