void setup() {
  // put your setup code here, to run once:
  pinMode(A4, OUTPUT);
  pinMode(9, OUTPUT);
}
//some pins have unique sign, those pins work as both digital and analog pins
void loop() {
  // put your main code here, to run repeatedly:
  analogWrite(A4,225);
  delay(1000);
  analogWrite(A4,0);

  analogWrite(9,100);
  delay(1000);
  analogWrite(9,0);
}