Math problems of the day for 7/12/26.

This interactive animation shows how the structure of the global export trade network changed from 1993 through 2025 using a constant set of countries included throughout the study period. Countries are grouped into subnetworks using the Leiden community-detection algorithm applied to directed, weighted bilateral import data from the IMF. Each color represents a detected trade subnet in a given year, and the timeline allows viewers to follow changes in countries’ subnet memberships over time. Subnet numbers are algorithmic labels and should not be interpreted as fixed groups across all years.