Cairo explains that “form follows function” is not 100% accurate because this would suggest that it is unidirectional when in fact the two are bidirectional in relation. The problem with this statement is that it assumes all things with a similar form can be used for the same function. In his book he uses an example of a spoon having a concave build allowing people to use this as a tool for scooping. He then compares an iPod wheel, also with a concave build which would not be used for scooping. Another issue addressed is the bubble charts. Bubble charts can be misleading when they are used to compare data size with the size of the circles in the charts. This is because the human mind has a hard time comparing the surface area of a circle as a pose to the area of a rectangle. However, bubble charts look good and are decorative and therefore people will use them. In some instances they can be very beneficial but that is determined by the goal. In Cairo’s example he uses a a bubble chart to identify the general patterns of concentration when it comes to voting for Republicans and Democrats.