Odd map out

Britain, Canada, Australia, and the United States share much in their political systems, including bicameralism, federalism in the case of the latter three, single-member electoral districts for national-level elections, and, with the wonderful wrinkle of Australia's preferential balloting system, first-past-the-post voting for elections to the lower house of the national-level legislature.

Still, one of these things is decidedly not like the others. Here are the national-level electoral maps of the largest cities in each of the four countries, starting with the central urban portion of Sydney, New South Wales, Australia:

Toronto, Ontario, Canada:

London, England, United Kingdom:

And New York, New York, U.S.A.:

The truly scary thing: New York's not even the worst. Try Miami. Or Chicago.