You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Like if you're going to *derive* sigma-delta and explain how it works and why, sure, use the mathematical model. But if you're going to just say "this is how you do it" then don't, and *especially* don't cook up a terribad implementation from it and present it as gospel.
Like I couldn't for the life of me figure out what the fuck was going on until I realized (after looking at other resources) that the bottom box is a *negation* in their implementation.
