int LED=8;                // Sets LED = 8
int flash = 1000;        // blinking rate 1000th seconds  (ms)

void setup() 
{
    pinMode(LED, OUTPUT);   //Pin 13 controls onboard LED and sets it ready for output 
    pinMode(LED+1, OUTPUT);
}

void loop() 
 {
  digitalWrite (LED, HIGH); //Turns on onboard LED
  digitalWrite (LED+1, HIGH);
  
  delay(flash);               //Pauses by the value of flash in 1000th of seconds

  digitalWrite (LED, LOW);  // Turns off onboard LED
  digitalWrite (LED+1, LOW);

  delay(flash);             // Pauses by the value of flash in 1000th of seconds
}