int led[] = {23, 22, 21, 19, 18, 5, 4, 26, 25, 33, 32, 34}; 
void setup() 
{
  // put your setup code here, to run once:
  int i = 0;
  for(i = 0; i < 12; i++)
  { 
    pinMode(led[i], OUTPUT);
  }
}


int pin = 0;
void loop() 
{
  // put your main code here, to run repeatedly:
  if(pin == 12)
  {
    pin = 0;
  }else{
    digitalWrite(led[pin], HIGH);
    delay(100);
    digitalWrite(led[pin], LOW);
    delay(100); // this speeds up the simulation
    pin++;
       }
}