The letters

After stating its system in brief, the 1446 book explained the letters one class at a time: the initial consonants, the vowels, the final consonants. Each class was explained by the same method.

This part does the same for gog’s letters. The marks are the initial consonants: visible forms that draw nothing until a position says where they go. The positions are the vowels: x, y, and z, plus the scales that decide how a number, a category, or a date becomes a place on an axis. The refining channels are the finals: color, size, shape, pattern, opacity. Each is optional, and each earns the legend that decodes it. group and label are neither. group splits a mark without encoding anything, so it earns no legend, and it works like the space between words. label supplies a text mark’s words rather than refining them. play stands outside the syllable, the way faceting does: it cuts the plot into frames and plays them in order, and its chapter waits in the next part. Around the letters sit the chapters that finish a plot. Data, the table you bind once, opens this part, because nothing can be drawn until a table is named. The book’s data follows, saying where this book’s own tables come from and how to read one in your language. Setting vs mapping separates a column you map from a constant you set, and Transforms, which derives new values from your columns, closes the part.

Choosing a mark opens the letters themselves, and then each mark has a chapter of its own, fourteen in a row from point to edge. Every one follows the same template: what it draws, what it requires, what refines it, what derives from it, what you can set on it, and what it refuses. The last two are always the last two, under those names. That sameness is deliberate: it is the No Exceptions law applied to a book’s structure. Learning the second mark is faster than the first, and by the fifth you already know the shape.