*1:See also https://sumita-m.hatenadiary.com/entry/20160901/1472698104 https://sumita-m.hatenadiary.com/entry/20160905/1473001573 https://sumita-m.hatenadiary.com/entry/2019/10/05/084846 https://sumita-m.hatenadiary.com/entry/2019/12/31/023348 https://sumita-m.hatenadiary.com/entry/2020/01/11/024638 https://sumita-m.hatenadiary.com/entry/2020/01/15/094009 https://sumita-m.hatenadiary.com/entry/2020/01/16/084538