We selected 200D as the perfect flag material; anything heavier doesn’t fly well and the “back” doesn’t get enough ink, anything lighter feels cheap and won’t last very long.
During the 1960s and 1970s, as the environmentalist movement was developing in the USA, different individuals and organizations made several “ecology flags”. One of the contemporary flags that became more famous and is still used today is the “Ecology Flag”.
The flag also has a letter Θ or “theta” from the Greek alphabet that in old Greek was used as an abbreviation for “thanatos” meaning death. In the case of the Ecology Flag, it was also about making a symbolic message that humans cannot live on a dead planet.