Varvara Harmon - Artist and Illustrator - Original Paintings, Pen, Pencil Drawings
My friend does awesome ink drawings. I reckon you're going to like these. - Imgur
oak tree, drawing oaks, oak drawing
arthur guptill - Google Search
This image here explores line. Depending on how much pressure you put on your pencil, and how close the patterns you create are, you can produce either dark tones or sensitive tones.
Cross Contour Breadth | A cross-contour drawing uses lines that seem to move along the surface of the objects in the composition. These lines emphasize the volume of the objects by wrapping around them.