This is one of many videos based on G3 and C4. Each video has a new option for a third note to play with G3 and C4. Why those two notes? G3 and C4 create what is called a Perfect Forth. This sound is very sounding, pulling you inwards. The perfect forth is a very popular interval.
![Key of G: Karl](http://soundjourneystore.com/cdn/shop/articles/Grayson_crystal_singing_bowls_300x.jpg?v=1617192458)