Just when I thought I would not find any more revelations about the Tetrads...
Attachment 293
There are 19 years from 1949 to 1968.
There are 48 years from 1967 to 2015.
There are 19 years from 842 to 861.
There are 48 years from 795 to 843.
The symmetry continues.
There are 634 years from 162 to 796.
There are 634 years from 860 to 1494.
https://www.youtube.com/watch?v=Zp8km6DCkLo
