“the functionality of graphics often works in a metaphorical way that attempts to imbue the virtual world with a similarity to the real world (e.g., the desktop metaphor), which does not always display the same logic or affordances that would be apparent in the real world. (…) affordances occur only when we interact without having to think consciously about what we are doing.” (p85)
The graphic language displayed through the visual communication in a digital interface manifests itself in ways that do not translate the real world directly. How something physically works in the real world may not translate to a representation in the digital world. The subtleties of how an idea of, or a suggestion to, a call to action is visually communicated are nuanced and seldom pedestrian.