byte pin1 = 4;
byte pin2 = 6;
byte pin3 = 8;

void setup() {

  pinMode(pin1, OUTPUT);
  pinMode(pin2, OUTPUT);
  pinMode(pin3, OUTPUT);
}

void loop() {
  digitalWrite(pin1, HIGH);
  delay(1000);                    
  digitalWrite(pin1, LOW);
  digitalWrite(pin2, HIGH);
  delay(1000);  
  digitalWrite(pin2, LOW);   
  digitalWrite(pin3, HIGH);
  delay(1000);  
  digitalWrite(pin3, LOW); 
  delay(1000);  
  digitalWrite(pin1, HIGH);
  digitalWrite(pin2, HIGH);
  digitalWrite(pin3, HIGH);
  delay(2000);
  digitalWrite(pin1, LOW);
  digitalWrite(pin2, LOW);
  digitalWrite(pin3, LOW);
  delay(1000);
  digitalWrite(pin1, HIGH);
  digitalWrite(pin2, HIGH);
  digitalWrite(pin3, HIGH);
  delay(2000);
  digitalWrite(pin1, LOW);
  digitalWrite(pin2, LOW);
  digitalWrite(pin3, LOW);
  delay(1000);
  digitalWrite(pin1, HIGH);
  digitalWrite(pin2, HIGH);
  digitalWrite(pin3, HIGH);
  delay(2000);
  digitalWrite(pin1, LOW);
  digitalWrite(pin2, LOW);
  digitalWrite(pin3, LOW);
  delay(1000);
}