unsigned long ghz=millis();
unsigned long lhz=millis();

void setup() 
{
  pinMode(A2, OUTPUT);
  pinMode(A3, OUTPUT);
  pinMode(8, OUTPUT);  
}

void loop() 
{
  if(millis()-ghz>1500)
  {
    ghz=millis();
    tone(8,100,750);
  }
  if((millis()-lhz>1000))
  {
    lhz=millis();
    digitalWrite(A2,!digitalRead(A2));
    digitalWrite(A3,!digitalRead(A2));
  }
}