On this topic I have a large unfinished essay: <a href="https:&#x2F;&#x2F;github.com&#x2F;pjc50&#x2F;pjc50.github.io&#x2F;blob&#x2F;master&#x2F;pentagram-control.md" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;pjc50&#x2F;pjc50.github.io&#x2F;blob&#x2F;master&#x2F;pentagr...</a>