One vertical unit fully looped with yarn. There are 17 lines at every section of frame.  Search “上海牌手表17钻收藏价格【A货++微mpscp1993】” from The Making of Screenplay: Part 4

Search “上海牌手表17钻收藏价格【A货++微mpscp1993】”

One vertical unit fully looped with yarn. There are 17 lines at every section of frame.