int ledPin = 13; // Define interface 9 
void setup() { 
	pinMode(ledPin, OUTPUT); 
} 
void loop() { 
	// Three short flashes to represent the letter "S"
	for (int x = 0; x < 3; x++) {
		digitalWrite(ledPin, HIGH);   // Set LED to ON 
		delay(500);                   // Delay for 500 milliseconds 
		digitalWrite(ledPin, LOW);    // Set LED to OFF 
		delay(500);                   // Delay for 500 milliseconds 
	} 
	// Delay of 200 milliseconds to create a gap between letters 
	delay(200); 
	// Three long flashes to represent the letter "O" 
	for (int x = 0; x < 3; x++) { 
		digitalWrite(ledPin, HIGH);   // Set LED to ON 
		delay(1500);                   // Delay for 1500 milliseconds 
		digitalWrite(ledPin, LOW);    // Set LED to OFF 
		delay(500);                   // Delay for 500 milliseconds 
	} 
	// Delay of 100 milliseconds to create a gap between letters 
	delay(100); 
	// Three short flashes to represent the letter "S" again 
	for (int x = 0; x < 3; x++) { 
		digitalWrite(ledPin, HIGH);   // Set LED to ON 
		delay(500);                   // Delay for 500 milliseconds 
		digitalWrite(ledPin, LOW);    // Set LED to OFF 
		delay(500);                   // Delay for 500 milliseconds 
	} 
	// Wait for 5 seconds before repeating the S.O.S signal 
	delay(5000); 
}