The author, Dmitriy Skougarevskiy, created an interactive online map using CartoDB and Mapbox to visualize the "doughnut holes" in international waters, specifically the loopholes in the Law of the Sea. The doughnut holes are areas beyond 200 nautical miles from a coastline where both countries have a claim but neither can exclusively exploit marine resources. To create the map, Skougarevskiy used CartoDB to display the seabed profile and EEZ boundaries, which were obtained from an ESRI shapefile. He then added colors to the EEZs based on their sovereignty, using CartoCSS to style the polygons. The map also includes infowindows with information about each doughnut hole, including its location, description, and sources. Interactivity is enabled through hover effects, zooming, and clicking on individual doughnut holes. The resulting map provides a unique visual representation of these complex international waters.