Today’s exponential sum, like all the exponential sums on the site, is formed by drawing a line between consecutive partial sums of a series involving complex exponentials. The exponential sum page makes an image each day by putting the day’s month, day, and year into a formula.
Here’s today’s image
based on the sum
I use American-style dates—month, day, year—because that increases the day-to-day variety of the images compared to using the day in the first denominator.