Hi @FranciscoMateus, this is a test pattern of the radar. You can read more on this here:
https://community.windy.com/topic/13493/what-is-this/6?_=1600681067491

'Strange' behavior of the radar:
https://www.weather.gov/jetstream/radarfaq#everything
https://www.radartutorial.eu/15.weather/wx21.en.html