Visual activation of negative areas of white spaces... that illustrates the endlessly contextual and interactive nature of visual elements (pg. 61). Tufte is talking about the two step logic of 1+1=3 and how if you draw two black lines then you get a third image of the white space in the middle. I think Tufte means that creating paths and forming shapes can be made with using lines because of the white space in the middle. When we draw two lines a third visual image comes up and we can make out many different information designs using this technique therefore we can create a hierarchy of visual effects and use the smallest designs to demonstrate information design.