Horseman and Mamiya
12 and 12 researched events on one shared scale. Horseman 1933–present, Mamiya 1940–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.
Horseman1933–present · 12 events · 4 concurrent threads
Mamiya1940–present · 12 events
1 span collapsed, 6 years in total, where neither maker has a research point: 1934–1939. Collapsing keeps a short-lived maker readable beside a long-lived one; the years are removed from the drawing, never from the record.