// ex 1-a
void setup() {
  pinMode(6, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(4, OUTPUT);
}

void loop() {
  digitalWrite(2,HIGH);
  delay(5000);
  digitalWrite(2,LOW);
  delay(100);
  digitalWrite(4, HIGH);
  delay(2000);
  digitalWrite(4,LOW);
  delay(500);
  digitalWrite(6,HIGH);
  delay(4000);
  digitalWrite(6,LOW);
  delay(500);
}