One reason i think these tutorials are great is because the writing is concise and to the point. No extraneous words.

It follows the style of writing outlined in https://en.wikipedia.org/wiki/The_Elements_of_Style almost to a T:

    Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the writer make all his sentences short, or that he avoid all detail and treat his subjects only in outline, but that he make every word tell.

    — "Elementary Principles of Composition", The Elements of Style