/*
Blink
Turns on an LED on for two second, then off for two second, repeatedly.
This example code is in the public domain.
*/
 
void setup () {
  // Initialize the digital pin as an output.
  // Pin 13 has an LED connected on most Arduino boards:
  pinMode (13, OUTPUT);
}
void loop () {
  digitalWrite (13, HIGH); // set the LED on
  delay (2000); // wait for a second
  digitalWrite (13, LOW); // set the LED off
  delay (2000); // wait for a second
}