I just found a fun post on idsketching.com, that identifies the different types of sketching and drawing. The sketch on the left represents personal communication. Often referred to as doodling, they provide a person with an opportunity to visual think and work through ideas. These doodle sketches usually stay in the sketchbook.
This next image of cutting tools, represents the thinking drawing. These sketches are more focused, representing the progression of ideas and are often shared to others for feedback. Here is a quote from the author on this blog: “I see sketching as a means to and ends rather than the end all. When all is said and done, regardless of how flashy the sketch may be or how killer it may look, the essence of why we sketch ideas as designers is seeded in effectively communicating those ideas to our clients. Sketching is our language of communication.” Check out the Technical Sketch and Presentation Sketch and the humorous descriptions on this post.