Excercise 2

Part I:

Part II:

I changed the code to: 

 digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)

  delay(4000);               // wait for a second

  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW

  delay(7000);               // wait for a second

}

Part III

It's hard to make out, but the two leds are blinking at different rates.

Part IV