HTML5 Canvas Clock Experiment

Do I know HTML? I would say, "yes" but the HTML I learned 17 years ago is different than today's HTML. Every article or tutorial available out there says HTML5 is similar to HTML 4. As an experiment and exercise in how HTML5's <canvas> tag works, I did the below Canvas Clock tutorial found on the W3 Schools website (link at bottom).

The tutorial was very easy, and by doing it, I am not saying I know and understand exactly how the HTML5 <canvas> tag works on the production side of a magazine website or when and how it is used by big advertising firms to serve ads on peoples' iPhones or Android devices, but I did learn a few things from the tutorial. It must be pointed out, HTML5, is much deeper and 10 times more expansive of a markup language than HTML 4.