The black triangle implies a "crown" or "mountains on Treasure Island". If you remove the book cover, you will see the golden treasure. Broke the tradition of rectangle belly band and replaced it with an irregular mountain-shaped one, and emphasizes the idea that the book itself is Treasure Island. Chose a picture of an island to be applied at the fore-edge and split the painting into pieces and implant each piece in order according to the page number. The slight shifts during binding pages into a book have been used intentionally to convey "the foggy view of the Treasure Island".