*1:See also https://sumita-m.hatenadiary.com/entry/20161014/1476463918 https://sumita-m.hatenadiary.com/entry/2019/11/26/012021 https://sumita-m.hatenadiary.com/entry/2020/02/29/091917 https://sumita-m.hatenadiary.com/entry/2020/10/13/145602 https://sumita-m.hatenadiary.com/entry/2021/04/29/202826 https://sumita-m.hatenadiary.com/entry/2021/05/17/150608