so, i went looking for the math to make a slat absorber (a.k.a. a slot absorber – depending on whether you’re a glass-half-full or a glass-half-empty kind of person…) this week. turns out that, if you search for the equations to build one, you’ll probably get the wrong answer. this is most likely due to a typo in a book that got copied in the next edition of the same book, and then, through the power of the internet and a procedure used in elite circles called “copy-and-paste”, was widely distributed. my dad always said that practice doesn’t make perfect – it makes permanent. practice a mistake, and you’ll be stuck with it.