1. Change the length of the time that the LED is ON. You can make the LED
    look like a strobe light by making the “ON” time very, very short.

  2. Change the length of time that the LED is OFF. You will find out there is
    a shortest time (probably greater than 10 ms) below which you can’t see that
    the LED is turned off or not.

  3. Change the pattern. Tell the LED to make 3 short blinks, followed by a
    relatively long delay.

  4. Change the pattern again. Tell the LED to make 3 short blinks, followed by
    three long blinks, followed by three short blinks, followed again by a rather
    long delay. Congratulations! You have just made the LED blink out the
    equivalent of “SOS”!

  5. Re-write the sample sketch so that it turns on the LED one time, delays
    for 1 second, and then turns it off until the board is reset.