Every complex software system tends to have sub-systems that are in the process of being rewritten but stuck in limbo. I call this myself the Hydra, although it’s a term that doesn’t exist outside of my head.

The subject of second systems deserves a full essay but while I sit on it and finish the books I have in mind, let’s enjoy this gem from Artur’s blog:

A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over with a working simple system.

Gall’s law