“Shikenhani Kokomade” (しけんはんいここまで, lit. “The Test is Up to Here”), alternatively Onei-chan (おねいちゃん) or Onee-chin (おねえちん), is a rabbit doodle from a random high school girl's notebook, uploaded by her brother in a /news4vip/ thread that he started on January 1, 2005.¹⁾

For context, a /news4vip/ user from Saitama Prefecture started a 'live commentary' thread about her older sister taking a bath on January 1, 2005 and the users got too excited over her drawing for some reason. He would bring updates from 'ID:CWyQ2wHA', 'ID:yZhzeY1R', 'ID:4hn8gVdS', and 'ID:2haCngxY', then the thread got derailed after that since anybody could be talking about their sister at that point.

His older sister was born in the Year of the Snake (1990–1991), presumably aged 14–15 at the time, and she was in her second year of high school, a year ahead of her brother, attending a school in Shibuya. Additionally, we also learn that she visits the Narita-san temple, has duck faced, likes mecha or robots,²⁾ plays the PS2, and has light blue panties. Hey, isn't this a bit creepy…?

The character speaks in katakana and isn't very deep, but her simple design allowed her to be used in a variety of ways in her respective /gline/ thread. In the original photograph, the social studies notebook mentions Takahashi Korekiyo and the invasion of an unspecified island whose name was cut off in the photo, but we aren't really focusing on this.

　　 ∩∩
　　 | | | |
　　( ﾟωﾟ) 　＜ The test is up to here.
　 ｡ノДヽ｡ 　　　
　　　bb 

.　　∩∩
　　 | | | |
　　(ﾟωﾟ ) ＜ ?
　 ｡ノДヽ｡
　　　bb 

“Tsumari(In other words)” (つまり) is a minor AA character that seems to explain things in hiragana, but it didn't stick around long since it was difficult to use. In the original photograph, they would appear next to grammar notes. The character has mostly been forgotten to time, leaving the Touhou Project variant, Yagokoro Sensei, from a certain song.

In other words,
　　　 　 ∧__∧　ll 　　The strange creature would appear, like someone
　　　　 |(･)｡(･)| ( )　　had just remembered something and exclaimed
　 　 　 |ヾ三ｦ└'ﾉ 　　"that's right!" However, this creature saw limited
　　　　.|　　　　ｌ´　　　usage since nobody knew how to use it.

• In other words, 'tsumari' (つまり) can mean 'i.e.' (id est), 'in other words', 'that is to say', etc.

• Shikenhani Kokomade [Archive] - An archive of an archive on this character.
• Shikenhani Kokomade + Tsumari on the 2ch AA Illustration Project