Special materials on MEE C-027,28!!
From here, Takahiro's explanation

The scene where MEE spells and releases the magic power of the magic book.
The large eyeballs make it difficult to balance the picture when the eyes are closed.


Movement (screen) in close to camera requires a lot of fudging.

The magic book is activated.

The e-conte looked easy enough, but it was a lot of work.
I had to think about the letters and the colors, and it was very hard work.


After that, sticking material of book's letters on the book. (It's called 貼り込み/Harikomi in Japanese anime production)