I'm trying to embed https://ncase.me/remember/sims/ebbinghaus/?mode=0 onto a page using an iframe. However, when I do, it does not display any of the interactive elements. See https://codepen.io/UYasher/pen/yLXaPeo for the behavior in an iframe:

<iframe 
    style="width: 600px; height:370px;"
    will_source="https://ncase.me/remember/sims/ebbinghaus/?mode=0"
    scrolling="no"
    class="simulation"
    src="https://ncase.me/remember/sims/ebbinghaus/?mode=0"
>
</iframe>

How can I fix this issue so that the iframe shows all the elements present on the original page?

What I think is causing the issue: I think this occurs because the iframe is unable to load the scripts at the bottom of ncase.me page. I don't understand why this is, though, as javascript appears to work in some iframes. For example, in order for google maps to run, scripts in the contents of the iframe need to be loaded and run.