Summer:  East - Peoples' Liberation Army Unit 61398 in Pudong, Shanghai, China.

Rumored to be the Chinese army's hacking division, depicted in the photograph.

News stories of the time were widely implicating this particular group as having hacked into all sorts of American computer networks.

Posters on the wall include the Autumn 2014 2600 whistleblower cover, Mao Tse-Tung, and a fiber optic cable map of the United States.

The hacked Tesla Motors tweet was picked because of the use of the dragon in Chinese culture.

The number of retweets was -1, the square root of which is the imaginary number i - read into that what you will.

The number of favorites was 61398, which was the above unit's number.

The PLA logo is displayed beneath the tweet.

The hashtag of #joshua is a nod to the film WarGames.

The compass Easter Egg was a drone plane.