The size of the page is called folio, and folio is based on the whole paper. How many small pieces of paper are cut into a pair on each whole piece of paper? In China, it is customary to use geometric series to name folio. The size of the folded paper is folio, then folded into 4 sheets, then folded into 8 sheets, then folded into 16 sheets, then folded into 32 sheets, then folded into 64 sheets, and so on.