BiFold of US presidential election - visual enhancement.
(a) States are colored based on the fraction of elections for which they supported the Republican (red) or Democrat (blue) presidential candidate. (b) Lines are added to connect Carter (‘76) and Reagan (‘84) to their respective “supporting” states in those elections. The boldness of the lines are proportional to the number of supporting states. (c) Similar support representation for Bush ‘00 and Obama ‘12 illustrate the strong partisan nature of those elections.