Interesting that Japan does not seem to have used parchment (animal hide). Western scribes would use knives to scrape ink off old parchment documents to re-use them.
Honestly it has never been made explicit.
My take is that Mako is upset that Yuri is no longer dependent on her. In addition Yuri's increasing eccentricity offends her sensibilities. Mako has been lashing out at Yoshida for similar reasons.
Mako is endlessly fascinating. Just a giant bundle of repressed urges. She would talk endless shit about her “friends” if not for the goody goody facade.
That question is the core of this manga’s plot. That and the tension that will arise as the MC forms an emotional connection with the robot. Aoi (the robot) is illegal both on earth as a sex bot and in space as a self aware computer.
My only real complaint about the plot is how emotionally...