Apologies for how messy this is.. I know this is uploaded at night but i scribbled it in the morning.. really early in the morning >_>
I'm trying to find the original graph for this, it was from a personal art blog of someone doing portraits and other traditional art. Their graph was cleaner (well it was like pixel/ms paint?) And every since I saw it i've kept it in mind. Now when I want to EXPLAIN it to other people without the graph it self it's just confusing so i made my own till i can find the other one.
If you know what i'm talking about please let me know so i can credit them!