int pos = 0;
void setup()
{
  pinMode(8, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
}
void loop()
{
  noTone(8);
  tone(6, 6, 200); 
  delay(200);
  noTone(6);
  tone(7, 988, 500); 
  delay(500);
  noTone(7);
  tone(8, 1047, 300); 
  delay(300);
}