I don't think we should be busting our heads trying to figure out how she printed the paper - after all, in this series you make shurikens, kunais, toads, snakes, hawks, and even people out of nothing.
I also gave up a long time ago on Kishimoto explaining how those ultimate techniques are learned (Nagato using the spirit-eating-statue-which-I-forgot-the-name for the "first time"; who was the first person to summon something - apparently Rikkudou Sennin now - and how did he figure out how to do it? etc).
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