void setup() {
  // put your setup code here, to run once:
  //initial pin 13 as an output
  pinMode(13, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  sos();
  delay(1000);

}

void on(){
  digitalWrite(13,HIGH); // turn the LED on (high is the voltage level)

}
void off(){
  digitalWrite(13, LOW); // turn the LED off (low voltage level)

}
void dit(){
  on();
  delay(100);
  off();
  delay(100);
}
void dash(){
  on();
  delay(300);
  off();
  delay(100);
}


void sos(){
  // s
  for(int i=0;i<3;i++){
    dit();
  }
  // o
  for(int i=0;i<3;i++, dash());
  // s
  dit();
  dit();
  dit();
}

void morse_code(){

}