*1:See also https://sumita-m.hatenadiary.com/entry/20130408/1365437101 https://sumita-m.hatenadiary.com/entry/20150724/1437745163 https://sumita-m.hatenadiary.com/entry/2019/07/19/143942 https://sumita-m.hatenadiary.com/entry/2019/08/15/204221 https://sumita-m.hatenadiary.com/entry/2020/02/01/082038 https://sumita-m.hatenadiary.com/entry/2020/02/02/133228 https://sumita-m.hatenadiary.com/entry/2020/02/12/020430 https://sumita-m.hatenadiary.com/entry/2020/02/13/095451 https://sumita-m.hatenadiary.com/entry/2020/02/15/083534 https://sumita-m.hatenadiary.com/entry/2020/03/01/093003