Art and Stationery Supplies Design Bookmark Multi-function bookmark by Yong Zhang This is a multi-purpose bookmark with ruler and writing aid. Bookmarks and rulers on the market are separate products, written on blank paper Straight line is a new starting point of this design. Writing aids, very practical. The most important is in the learning process bookmarks, rulers And writing aids are often used, combining the three into one product, It's a very clever solution. Books and bookmarks are compatible, and with bookmarks there are other auxiliary tools.