There is this common, persistent and incredibly misguided belief among everybody I have ever spoken to that you need to be well versed in science and especially mathematics to be able to be a good computer programmer.
This has just been perpetuated here again in the comments.
Analytical skills is most definitely needed to be a good programmer, but mathematics and physics will not necessarily imbue those skills on you. There are many different ways to learn how to be analytical and critical in your thinking.
This is a very obvious and n00b mistake to make, and I am proud of my ignorance. When you remove a domain controller from a domain (not the last domain controller mind you), you do so by demoting it. In Windows 2012 R2 and newer the standard way is to uninstall the "Active Directory Domain Services" role from Server Manager, and selecting the "Demote this domain controller" option when prompted.
However, following this procedure will cause a reboot, and when you try to log in you may, if you were as ignorant as I was, find yourself locked out of the server. I tried to log in under the domain administrator account but got the error:
There are no logon servers available to service the logon request
This is a complicated and ongoing project. But here is a teaser...
Update: 26 May 2019 The table is finished.
Table salt is NaCl. It is a molecule of one sodium atom ionically bonded to one chloride atom. So reducing half of what defines table salt (sodium) by 50% changes this table salt to... 50% more chloride? Not good. This is the pinnacle of ridiculousness....