2. Extracting Essential Gestures and Contours

I think the idea of extracting the essential gestures and contours means taking a flat drawing such as the foot on the left and adding a series of lines that almost wrap around the different parts of the foot to add depth and make the drawing go from being flat to having some sort of dimension.  If you look closely at the big toe on the right you can see tiny lines wrapping right from just below the nail to under the foot.  This has given a depth and shadow to the toe.  The same is done in between the toes but with the lines wrapping left to create space between each toe.  This is different then just shading because it shows the direction the light hits the foot.