A CodePen Demo

CodePen is a neat site where you can provide some HTML, CSS and JavaScript, then share the live result, alongside the code, for other web developers to see, share, like, etc. You can even embed the result in a WordPress blog post. Here’s one I created (best viewed at 0.5x):

Drag the two sliders under the stacked circles to change their relative sizes.

You can read more about what I was thinking in the “details view” version of that pen.

A friendly human.