Although there have been some new developments in mathematics, such as the proof of the famous four-color theorem, 1 the basic material has remained unchanged.
虽然在数学领域也有一些新的进展，例如对著名的四色定理的证明，1但是基本的材料却保持不变。
2
As proof of these statements, consider an example coming from real life: Figure 1 depicts three different scenarios, described in a verbal format as current best practices recommend.
As you may recall from part 1, this multiple-part article covers Phase 1 of the project: a proof of concept resulting in a set of requirements, a reference architecture, and (ideally reusable) code.