Marie writes: Yarn Bombing. Yarn Storming. Guerilla Knitting. It has many names and all describe a type of graffiti or street art that employs colorful displays of knitted or crocheted cloth rather than paint or chalk. And while yarn installations may last for years, they are considered non-permanent, and unlike graffiti, can be easily removed if necessary. Yarn storming began in the U.S., but it has since spread worldwide. Note: special thanks go to Siri Arnet for telling me about this cool urban movement.