I think a couple of spots in the South Pacific, Indian Ocean and Caribbean show a few almost-Voronoi tiles, as Anton describes - there are areas where several island nations are in such close proximity that one or more EEZ is bordered completely by lines of equidistance. I think they probably fail to be perfect Voronoi tiles (thanks, Anton, for introducing me to the name) because the equidistance lines are based on coasts and baselines, and so don't represent perfect lines of equidistance from a single point. The *approximate* defining point must be somewhere near the geometric centre of the island nation, rather than at its capital, as Randy wanted.

BTW Randy: At least one nation has a ready-made monument in its national capital to measure distance from: in a park down by the river in Budapest there's a large concrete zero on a pedestal. It's the official zero milestone for the country - admittedly distances are measured along the roads at present, but the principle is there!

Grant