Some tachymeter/telemeter/pulsometer watches featured spiral-model “snailed” scales about the dial. With the Chronoscope, Omega opted for a more symmetrical seem that features a handful of concentric circles which include the essential scale information even though also not materially distracting from Main dial legibility. Later examples can be found from the https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/