Interesting write up. There was a claim I didn't understand though

> Let’s fix this. An easy way to get our std::vector implementation in-line with the rest of the containers is we can sort it and utilize an algorithm, std::lower_bound, in order to speed up our lookup times.

Unless I'm missing something, isn't this wrong? The point of the vector is that v[enum_value] gives you the name of enum_value as a string. Once you sort it this relationship no longer holds, unless it so happens that the vector was already sorted (which happens to be the case for "circle", "square", "triangle").