Amnesty International 'fence' by Brothers and Sisters
Brothers and Sisters has created a series of street art for Amnesty International which appears invisible until it's viewed from a particular angle.
The campaign highlights the case of Troy Davis, a man who has been on death row for 19 years in the US, despite serious doubts about his conviction.
The posters are displayed on fence railings. From the front view, you see nothing but bars. Troy’s face only becomes visible from an angle. A plaque on the fence directs passers-by to a site where they can sign a petition to stop Troy’s execution.