void setup() {
  // put your setup code here, to run once:
pinMode(3, OUTPUT);
pinMode(13, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
analogWrite(3,150);
analogWrite(5,200);
analogWrite(6,250);
delay(250);
analogWrite(3,250);
analogWrite(5,150);
analogWrite(6,200);
delay(250);
}