As basic rules of a language must be practiced continually, and therefore are never fixed, so exercises toward distinct color effects never are done or over. New and different cases will be discovered time and again.
At one time I thought the Editor of the Lancet would kindly publish a letter from me on the subject, but further reflection led me to doubt whether so insignificant an individual would be noticed without some special introduction.
I never have been insecure, because I see what a waste it is. I know there is a solution to insecurity. I don't tend to be thrown by problems that don't have solutions. And insecurity has a wealth of alternatives.