*1:See also https://sumita-m.hatenadiary.com/entry/2020/02/20/212628 https://sumita-m.hatenadiary.com/entry/2020/04/06/014410 https://sumita-m.hatenadiary.com/entry/2020/07/25/080501 https://sumita-m.hatenadiary.com/entry/2020/08/11/095935 https://sumita-m.hatenadiary.com/entry/2020/10/01/092639 https://sumita-m.hatenadiary.com/entry/2020/12/19/170924 https://sumita-m.hatenadiary.com/entry/2021/01/03/090242