Some tachymeter/telemeter/pulsometer watches featured spiral-style “snailed” scales on the dial. For your Chronoscope, Omega opted for a far more symmetrical look that contains a couple of concentric circles that include the essential scale info even though also not materially distracting from Main dial legibility. Later examples are available from the https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/