void setup()
{
  pinMode(2,OUTPUT);
  pinMode(3,OUTPUT);
  pinMode(4,OUTPUT);
}
void loop()
{
  digitalWrite(2, HIGH);
  delay(6000); // Wait for 6000 millisecond(s)
  digitalWrite(2, LOW);
  digitalWrite(3, HIGH);
  delay(1500); // Wait for 1500 millisecond(s)
  digitalWrite(3, LOW);
  digitalWrite(4, HIGH);
  delay(4000); // Wait for 4000 millisecond(s)
  digitalWrite(4, LOW);
}