The London Tube logo (a.k.a. "The Roundel") has been around for over 100 years, and as such, 100 artists were commissioned to re-interpret it for the book, The Roundel: 100 Artists Remake a London Icon. From paintings to drawings, prints, and sculptures, each piece pays homage to the work of calligrapher Edward Johnston, who wanted to achieve "a balance between order and freedom, the classical age, and modernity."

[via Treehugger]