void setup() {
  // put your setup code here, to run once:
pinMode(2, OUTPUT);
}
int d = 0;
int f = 0;
void loop() {
  d = random(30,50);
  f = random(200,8000);
  tone(2,f);
  delay(d);
  noTone(2);
  delay(d);
  

  // put your main code here, to run repeatedly:
}