*1:See also https://sumita-m.hatenadiary.com/entry/20130413/1365875653 https://sumita-m.hatenadiary.com/entry/2019/10/28/100855 https://sumita-m.hatenadiary.com/entry/2019/12/24/023148 https://sumita-m.hatenadiary.com/entry/2020/01/14/095940 https://sumita-m.hatenadiary.com/entry/2020/02/06/024603 https://sumita-m.hatenadiary.com/entry/2020/02/15/083534 https://sumita-m.hatenadiary.com/entry/2020/02/23/140647 https://sumita-m.hatenadiary.com/entry/2020/03/05/033241
