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xkcd #3121: Kite Incident
(imgs.xkcd.com)
Title text:
Detectives say the key to tracking down the source of the kites was a large wall map covered in thumbtacks and string. 'It's the first time that method has ever actually worked,' said a spokesperson.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3121/
So, a little less than a year. Working on building kites. For free. Yeah, I'm not going to do that.