Hi there, this is an excellent lesson regarding Crosshatching, which is most useful in combination with other methods, anything goes as long that we can reach closest to the original intention which was set in the mind from the time we had the desire to express an idea or concept, be for our own satisfaction or for expressing an idea for others to see. Drawing is a form of human expression, just as much as writing although even more powerful, as the emperor of France Napoleon I once said to its generals on the battlefield, give me a sketch of what you have seen, it will speak better than a thousand words. Indeed, drawings are so powerful that states including the one of the USA are attempting to use strong laws of censorship to stop artists to exhibit their drawings if the content displease the establishment. Confiscation of artworks by authority is becoming quiet common now even more so than in the past, so, drawing is a very powerful medium and to excel in it is to be encouraged by all means. So, this particular website in my view is great in many aspects.
Thank you for your attention