void setup() {
 
  int x=1;
  while (x<=6) {
    pinMode(x, OUTPUT);
    x=x+1;
  }
}

void loop() {
int left=1;
while (left <=6){
  digitalWrite(left,HIGH);
  delay(500);
  digitalWrite(left, LOW);
  delay(500);
  left=left+1;
}
 
   // put your main code here, to run repeatedly:

}