Answer: Lines are the most basicand most important elements of design. They come in all shapes, sizes, and colors. Once you start noticing them, you'll see grids all around you. Lines have direction; they can be visible or invisible and can help direct the eye to a specific spot. Hierarchy is an important principle of design that directly relates to how well content can be processed by people using a website. It refers to the importance of elements within a design. The most important elements (or content) should appear to be the most important.
It can help others go through the 4 stages of art critism like judge, interpret, decribe and analyze. You can not do that if you have nothing to analyze about the art work
