*1:See also https://sumita-m.hatenadiary.com/entry/20131226/1388067636 https://sumita-m.hatenadiary.com/entry/20170306/1488767491 https://sumita-m.hatenadiary.com/entry/2019/09/11/090059 https://sumita-m.hatenadiary.com/entry/2020/06/11/101747 https://sumita-m.hatenadiary.com/entry/2020/07/14/224419 https://sumita-m.hatenadiary.com/entry/2020/08/17/100706 https://sumita-m.hatenadiary.com/entry/2021/06/19/114040