In the chapter Layering and Separation, Edward Tufte argues that one must be aware of how visual objects interact with one another when appearing on the same surface, summed up in the statement “1+1=3”. This comes from a specific example of two lines next to each other creating a third one between them, but can be extended to any situation where the negative space between elements becomes as attention-grabbing as the elements themselves. These situations are to be avoided in order to convey information clearly, Tufte argues, and follows with numerous examples of bad graphic design and how it can be turned good with only minor tweaks; usually removing unimportant elements, reducing contrast created by supporting shapes and differentiating elements using line weight and color instead of exessive lines and descriptions.