A thin crescent moon rotates to show it's position in the lunar cycle.
This is one of the many faces of Disk Clock.
Day Disk https://chrome.google.com/webstore/detail/ombigfjidloamaacoapfbanggkmekkhd
Disk Clock https://chrome.google.com/webstore/detail/mgnkijdpagnigijnlnbofmjdpjjmhnpm
谷歌浏览器、其他Chromium内核的浏览器