For the curious, [1] (via [2]) shows various engine designs.<p>[1] <a href="https:&#x2F;&#x2F;imgur.com&#x2F;gallery&#x2F;bxzeN" rel="nofollow">https:&#x2F;&#x2F;imgur.com&#x2F;gallery&#x2F;bxzeN</a>
[2] <a href="https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;educationalgifs&#x2F;comments&#x2F;468290&#x2F;a_collection_of_gifs_demonstrating_a_few&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;educationalgifs&#x2F;comments&#x2F;468290&#x2F;a_c...</a>