*1:See also https://sumita-m.hatenadiary.com/entry/20060602/1149248358 https://sumita-m.hatenadiary.com/entry/2020/03/08/100423 https://sumita-m.hatenadiary.com/entry/2020/09/16/125832 https://sumita-m.hatenadiary.com/entry/2020/10/08/111156 https://sumita-m.hatenadiary.com/entry/2020/11/14/094652 https://sumita-m.hatenadiary.com/entry/2021/02/11/020233 https://sumita-m.hatenadiary.com/entry/2021/03/08/102851 https://sumita-m.hatenadiary.com/entry/2021/03/09/094435 https://sumita-m.hatenadiary.com/entry/2021/05/06/084544 https://sumita-m.hatenadiary.com/entry/2021/05/12/095531 https://sumita-m.hatenadiary.com/entry/2021/06/03/073508