Just minutes ago, at the ATypI conference in Warsaw, the world was introduced to a new kind of font: a variable font. Jointly developed by Apple, Google, Microsoft, and Adobe, a variable font is, as John Hudson put it, “a single font file that behaves like multiple fonts”.
http://blog.typekit.com/2016/09/14/variable-fonts-a-new-kind-of-font-for-flexible-design/amp/