*1:See also https://sumita-m.hatenadiary.com/entry/2020/03/01/093003 https://sumita-m.hatenadiary.com/entry/2020/03/15/094840 https://sumita-m.hatenadiary.com/entry/2020/03/23/092958 https://sumita-m.hatenadiary.com/entry/2020/03/23/130845 https://sumita-m.hatenadiary.com/entry/2020/04/05/135314 https://sumita-m.hatenadiary.com/entry/2020/04/15/133650