bs0d3 writes: Canada Post has filed a copyright infringement lawsuit against Geolytica, which operates GeoCoder.ca, a website that provides several geocoding services including free access to a crowdsourced compiled database of Canadian postal codes. Canada Post argues that it is the exclusive copyright holder of all Canadian postal codes and claims that GeoCoder appropriated the database and made unauthorized reproductions.
We warn the reader in advance that the proof presented here depends on a
clever but highly unmotivated trick.
-- Howard Anton, "Elementary Linear Algebra"