Every time I think I know what's going on, suddenly there's another layer of complications.
https://rpubs.com/enwuliu/1443160
https://rpubs.com/enwuliu/1442659
https://rpubs.com/enwuliu/1441980
https://rpubs.com/enwuliu/1441487
https://rpubs.com/enwuliu/1439251
Just a note,