Sometimes I'm not sure if I'm very dense or very clever...

I just looked up the definition of a term in the IRS regulations of a word used in the IRS statutes, and it seems that the decemal numbering of section 1 of title 26 of the CFR tracks the numbering of title 26 of the US Code. Do other regulations do that, or is it just the IRS? I've only noticed the corrolation between 26 CFR and 26 USC. Am I just not noticing this in other sections?