It is said ''(source, please?)'' for every feature there is a two hour, a two day and a two week version.

I believe SteveMcConnell said this in RapidDevelopment, and used the example of a graphing subsystem. You can hardcode the colors (for the individual bars/lines) and symbols for points (star, cross, etc.), which is the 2 hour version, or you can use an increasingly more flexible scheme, up to where you have a GUI for choosing colors & symbols (the 2 week version).

See also EstimationWoes, especially for the derivation of the term "CuplaDays".