I have become aware of a couple of errors I made in my most recent 2 previous posts (1 in each post), and am now taking the opportunity to correct them.
In my post about the trig function puzzle I wrote "... integer multiples of π/4 rad (= 45°) and integer multiples of π/6 rad (= 30°) . Besides these angles, (and perhaps a few that are accessible by half-angle formulas like 22.5° or 30°) pretty much for nearly all other angles ...". But what I had meant to write was "..., (and perhaps a few that are accessible by half-angle formulas like 22.5° or 15°)...".
Also in my most recent post I mentioned "... the Chinese story of the 5 blind men and the elephant ...". As JSD graciously pointed out off-list the story's origin has been traced to India, and later spread elsewhere from there, including China. So I should have written "... the Indian story of the 5 blind men and the elephant ...".