Four patterns of historical events show up throughout world history:
Linear where events follow one line of development;
Convergence where 2 or more events or factors converge to create 1 result;
Divergence where 1 event or factor has 2 or more results; and
Feedback models where 2 or more events or factors feed back on one another to create a recurring cycle.
In order to make the patterns more recognizable, memorable, understandable, and interesting, the flowcharts use three design elements: simplicity, bilateral symmetry, and color. Each flowchart's design is also determined by the nature of the historical material and thus reflects that period's uniqueness.
However, each flowchart's design is also determined by the nature of the historical material and thus reflects that period's uniqueness. Although certain general patterns (e.g., feedback cycles) tend to recur, the information in each pattern is specific to that topic. As the patterns become more recognizable, readers become more adept at understanding the material.
The elements are color-coded as follows:
Links to other flowcharts have a heavy black border, round corners, white background, and blue text.
New pieces of information, information is not linked to any previous box, have square corners, and light-red backgrounds. This is especially used for acts of nature such as epidemics or changes of climate.
Two or more boxes describing a feedback model are enclosed in a box with a bright red background.
Two or more feedback models that feed back on each other are enclosed in a box with a light orange background. This is also used to show how a feedback model leads into and is reinforced by a sequence of specific events.
A general concept is shown in black text over a light blue background, with supporting or relevant information in connected boxes below it. This organizes the flowchart into smaller and and easily digested units to help understanding of the whole flowchart.
A process that is part of the larger flowchart is grouped in a large box with a light green background. This also breaks up the flowchart to aid in understanding.