*1:See also https://sumita-m.hatenadiary.com/entry/20161011/1476112393 https://sumita-m.hatenadiary.com/entry/20181005/1538730662 https://sumita-m.hatenadiary.com/entry/2019/09/21/094840 https://sumita-m.hatenadiary.com/entry/2020/06/29/131848 https://sumita-m.hatenadiary.com/entry/2020/09/20/073905 https://sumita-m.hatenadiary.com/entry/2021/06/20/014022