a hybrid font
there are a few notable typefaces out there that have both a serif AND sans serif treatment. even fewer are the fonts that attempt to bridge the divide with pseudo-sans and proto-serifs. rotis by top german designer, otl aicher is just such a font.
it is worth noting that the r in rotis is not meant to be capitalised since aicher, like yours truly, believes that capital letters are a sign of hierarchy and oppression. via ragbag