Periodicity or structural repetition in the scattering medium will cause interference in the spectrum of scattered light.
These so-called Heinrich events, named after their discoverer Hartmut Heinrich, appear to have a 7,000–10,000-year periodicity, and occur during cold periods within the last interglacial.
The political rock band Redgum recorded part of her poem "Periodicity" set to music as "Women in Change" on their 1980 album Virgin Ground.
Type 1 Second-degree AV block, also known as Mobitz I or Wenckebach periodicity, is almost always a disease of the AV node.