*1:See also https://sumita-m.hatenadiary.com/entry/2020/02/01/120310 https://sumita-m.hatenadiary.com/entry/2020/06/17/090112 https://sumita-m.hatenadiary.com/entry/2020/08/05/075820 https://sumita-m.hatenadiary.com/entry/2020/11/02/102532 https://sumita-m.hatenadiary.com/entry/2020/11/11/085545 https://sumita-m.hatenadiary.com/entry/2020/11/17/105226 https://sumita-m.hatenadiary.com/entry/2021/02/05/020243 https://sumita-m.hatenadiary.com/entry/2021/02/06/090400 https://sumita-m.hatenadiary.com/entry/2021/02/12/124344