Incidental Redundancy

> I humbly submit to you the concept of “incidental redundancy”. Incidental redundancy is a repetition of code syntax or semantics that tempts the programmer to refactor, but if carried out the refactoring could damage the elegance and discoverability of the program.

via Turbulent Intellect: Incidental Redundancy.

The use of parallels from physics is a skill close to my heart.