Multiple Master fonts, developed by Adobe, contain several sets of outlines that represent either end of up to font ‘design axes’: weight, width, style, and optical size.
Using a software utility, designers can create custom fonts by choosing points between these extremes.
The result is not a distortion of the original letterforms but a newly generated font.
Sadly only a few Multiple Master fonts have appeared, and they are not directly supported in either Windows or the Mac OS.