I've found another[1] on a blog post[2], captioned as follows:

  Frontispiece 1. Art drawn by chimpanzee Ai using sharpies(Saito, 2008)[p.19]
  Frontispiece 2. Art styles of 4 adult chimpanzees(Saito, 2008). Guess which one was by Ai[p.20]

Not sure what the background of the author is, but this essay/lecture note discusses ego or literal self-awareness of apes contrasted against human children, using quotes from books. Apparently apes don't exhibit explosive growth of vocabulary, show use of syntax etc etc, and are therefore not able to acquire language. The post later also argues their ego may be on the edge of formulating but must be weak/incomplete.

There's also magazine excerpt[3] on a page on relevant Kyoto University research center comparing an inpainting task done by a chimpanzee and a human child of 3 years old, showing that chimpanzees can only recognize and trace existing patterns, whereas kids go and complete the face with eyes, nose and mouth.

  1: https://kyoikugenri2019.up.seesaa.net/image/2017-10-132018.11.52.jpg
  2: https://kyoikugenri2019.seesaa.net/article/471281414.html
  3: https://www.wrc.kyoto-u.ac.jp/ja/publications/AyaSaito/kagaku084.html