The "Build a random quote machine" codepen example doesn't work

Hi,
In the “Build a random quote machine” page, the Codepen example provided doesn’t work well… it doesn’t show any quotes and it looks as if it has a bug somewhere. I’m using google chrome (v66.0.3359.139), if that matters.

I understand the task thanks to the video, but the example linked to in the page doesn’t work…