I found this song to be interesting due to its simplicity. Ca Tru is a Vietnamese traditional song. It has a simple rhythm carried by one person with two hitting sticks. An instrument very similar to the moon lute carries the melody. There is also a small drum that is hit twice in succession and has 14 beats of rest between the double hits. There are 2 singers, that sing over the melody that the string instrument is playing. There are 4 people involved in total. I found the recording on Youtube.