I really love the above shoe drawing because of the intricate detail put into it.
It's one of the first conceptual drawings of the shoe and it really just shows the finer elements of the design. It's almost like the drawing step before they designer applies the shoe into a 3D sense; ie. putting the shoe on a foot.
I really really admire the two above ring drawings because jewellery is the field I want to pursue and from making jewellery in the past I have discovered how difficult it is to portray exactly what you are trying to design and make within a drawing. I think both drawings, especially the bottom one, allow the viewer to see what each ring would look like in reality. The bottom drawings are very sketchy with cross-hatching backgrounds which push the main drawings out, I like this idea and want to learn how to do this with my own drawings.