"Tree Diagram" (樹形図の設計者 (ツリーダイアグラム) Tsurī Daiaguramu?, lit. "Designer of the Tree Diagram") is the twelvth episode of the second season of the Toaru Kagaku no Railgun anime series, and the 36th episode of the series overall. It was first aired on June 28th, 2013. The script was written by Hanada Jukki, directed by Nihei Yuuichi, and storyboarded by Sonoda Masahiro. The animation was co-directed by Matsumoto Fumion, Fukuyo Takaaki, Hayashi Saitoku, and Furusawa Takafumi.