<P> Digital fonts may also contain data representing the metrics used for composition, including kerning pairs, component creation data for accented characters, glyph substitution rules for Arabic typography and for connecting script faces, and for simple everyday ligatures like fl . Common font formats include TrueType, OpenType and PostScript Type 1, while Metafont is still used by TeX and its variants . Applications using these font formats, including the rasterizers, appear in Microsoft and Apple Computer operating systems, Adobe Systems products and those of several other companies . Digital fonts are created with font editors such as FontForge, RoboFont, Glyphs, Fontlab's TypeTool, FontLab Studio, Fontographer, or AsiaFont Studio . </P> <P> Typographers have developed a comprehensive vocabulary for describing the many aspects of typefaces and typography . Some vocabulary applies only to a subset of all scripts . Serifs, for example, are a purely decorative characteristic of typefaces used for European scripts, whereas the glyphs used in Arabic or East Asian scripts have characteristics (such as stroke width) that may be similar in some respects but cannot reasonably be called serifs and may not be purely decorative . </P> <Table> <Tr> <Td> </Td> <Td> Sans serif font </Td> </Tr> <Tr> <Td> </Td> <Td> Serif font </Td> </Tr> <Tr> <Td> </Td> <Td> Serif font with serifs highlighted in red </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> Sans serif font </Td> </Tr>

Which of the following is not an example of varying document design