int ledPin1 = 2;
int ledPin2 = 3;
int ledPin3 = 4;

void setup() {
  // put your setup code here, to run once:
  pinMode(ledPin1 , OUTPUT);
  pinMode(ledPin2 , OUTPUT);
  pinMode(ledPin3 , OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  analogWrite(ledPin1 , HIGH);
  delay(200);

  analogWrite(ledPin1 , LOW);
  delay(200);

  analogWrite(ledPin2 , HIGH);
  delay(200);

  analogWrite(ledPin2 , LOW);
  delay(200);

  analogWrite(ledPin3 , HIGH);
  delay(200);

  analogWrite(ledPin3 , LOW);
  delay(200);

}