*1:See also https://sumita-m.hatenadiary.com/entry/2020/07/12/222257 https://sumita-m.hatenadiary.com/entry/2020/07/22/123612 https://sumita-m.hatenadiary.com/entry/2020/07/30/134649 https://sumita-m.hatenadiary.com/entry/2020/08/23/160606 https://sumita-m.hatenadiary.com/entry/2020/09/20/020937 https://sumita-m.hatenadiary.com/entry/2020/12/01/103123 https://sumita-m.hatenadiary.com/entry/2021/01/08/085558 https://sumita-m.hatenadiary.com/entry/2021/01/17/130116 https://sumita-m.hatenadiary.com/entry/2021/01/27/083235