Font Variation
see https://www.microsoft.com/en-us/Typography/FontVariationsAnnouncement.aspx
https://alistapart.com/column/font-hinting-and-the-future-of-responsive-typography
https://medium.com/@tiro/https-medium-com-tiro-introducing-opentype-variable-fonts-12ba6cd2369
https://opensource.googleblog.com/2016/09/introducing-opentype-font-variations.html
on win10, see Microsoft's new Bahnschrift
see also => Glyph Analysis (https://github.com/PaintLab/PixelFarm/issues/4)
Variable Fonts ...
https://github.com/weiweihuanghuang/Work-Sans
https://github.com/eliheuer/titillium-web-vf
https://github.com/googlefonts/noto-fonts/releases/tag/v2.6-SlimVF-InitialVersion
https://web.dev/variable-fonts/