Polaroid and Zeiss Ikon
12 and 9 researched events on one shared scale. Polaroid 1932–present, Zeiss Ikon 1926–present.
The axis stretches where either maker has research and collapses where neither does, so a year sits opposite the same year on both. Event counts differ because research depth differs, not because one company did less.
Polaroid1932–present · 12 events · 3 concurrent threads
Zeiss Ikon1926–present · 9 events · 5 concurrent threads
Read either maker on its own: Polaroid · Zeiss Ikon