Graphs are data structures that model relationships between objects. Traditionally, graphs are directed, meaning that the relationships between objects have a specific direction. However, an interesting approach is the use of undirected relational graphs.

Global Temperature Histogram from 1950 to Present Day. The spiral is interesting in that it allows for a non-linear approach to events. It combines both the linear aspect of a line and the cyclical nature of a circle. Time is often represented as a line to evoke its linear and infinite nature, or as a circle to emphasize the concept of cycles.