I don’t know if anyone else caught this but it tripped me up just a little bit when it kicked into the exercise. I believe the statement was supposed to say WORD_LENGTH but it was spelled out WORLD_LENGTH in the video example. It doesn’t seem to matter as either way it still performs the function intended. Any way just an observation 
And then my wife pointed out to me the banner at the top that says “Excuse the Typo, it’s fixed in Lecture 30”