Triangular Plot

http://www.ex-parrot.com/~chris/wwwitter/20050407-it_doesnt_matter_how_you_vote_either_way_your_planet_is_doomed.html

Triangular plots are used to represent three different data sets at the same time. For this map in particular, it is representing three different major political parties, the Liberal Democrat vote, Conservative vote, Labour vote, and their percentage to win over majority of the parliament in the UK. The white circle in the middle is to represent the current estimate from the opinion polls.