*1:See also https://sumita-m.hatenadiary.com/entry/20150730/1438223216 https://sumita-m.hatenadiary.com/entry/2020/04/06/014410 https://sumita-m.hatenadiary.com/entry/2020/05/18/091354 https://sumita-m.hatenadiary.com/entry/2020/12/23/133417 https://sumita-m.hatenadiary.com/entry/2021/02/02/144734 https://sumita-m.hatenadiary.com/entry/2021/02/06/185051 https://sumita-m.hatenadiary.com/entry/2021/03/04/212712