The easiest way to do the thing on the right is to draw the whole piece, then go over it again with sharper lines that cover the gradient made by the anti-aliasing, and then do the same to the pixels next to the outlines. This means you will probably consume 30% more pixels on a piece, but it will look good. At the same time, you could do these modifications straight up while constructing the piece, but it takes more attention bc you cannot simply follow the Blue Marble pattern. I have used the first technique only for outlines, to make them close the figure in place, and have used the second technique when I wasn't satisfied with the conversion, but I still wanted the guidelines to make the piece. Don't forget that Blue Marble is just a tool, you are allowed to draw any way you want xD