Hidden in this post is an Easter egg of sorts. Searching for it will be easy for experts, difficult for puzzle novices. This is the kind of brain teaser easily dispatched by veterans. The sole clue that I will give you is that the solution involves a simple progression.
I search for these sort of things systematically, and so should you. Break in a new pencil, for you’ll need some sort of writing tool; maybe a scratch pad.
Letters? There are ten—in the solution, I mean.
Oh that’s a new clue, I just realized. Happy muff!