I did my last serious research work in 2009 (age 75 at that time). Since then any technical writing I do are of the broadstorke/explanation kind rather than attempting breakthrough to new frontiers. I spend my time writing blogs to explain S&T and life in these united States. Occasionaly I go to interesting talks just to test that I can still follow it and write a summary afterward to show that I unstoood it. Cognitive function like physical abilities unaviodably declines with age. Scientific researchers like althiletes should retire and not try to compete with their younger peers. This is a fact of life everyone acknowldges. According to my mental exercise app, my composite cognitive  function has decline about 7-8% from my peak which is not noticeable in everyday social interactions and daily living tasks,

Today, out of curiosity I happen to read a review article about the origin and properties of Gaussian probability distribution. In my active research days, I eat, drink, and dream about Guassian probabilty distributions. But reading the artidcle today I was suddenly reminded of facts you use to know but have forgotten. I wasn't surprised nor depressed. But this does remind me of the fact noted in the title of this article. I am satisfied with my life.  And to paraphrase the nuance of the Frank sSnartra signature song - I lived my American dream and did it mny way!