What dynamic explains the consistent saw tooth oscillation of Covid?

Question

https://www.worldometers.info/coronavirus/See the charts here. The oscillations are pretty consistent having a 'wavelength' of maybe 7 - 10 days. The amplitude of these smaller saw-teeth atop the 'spine' of the larger trend seems to be a function of height of the spine. What could explain consistent short-duration saw-teeth like this?

high_byte · Accepted Answer

I'll jump in saying "Weekends" but add the following fun bonus: https://www.npmtrends.com/react-vs-vuethe dips are Christmas.

robthebrew · Answer

Weekends, as Tomte said. No testing for 2 days then a backlog to clear during the week.

Tomte · Answer

Weekends.