>>...almost anyone can memorize a very strong password. The bad news, though, is that doing so required 20 to 30 training sessions no less than half an hour apart, and that the password could be forgotten if not used regularly

That applies to random strings of letters and numbers. However a string of words is as secure (or likely more as the 'alphabet' of words is much larger than the one of alphanumeric characters). The trick is to come up with a mental picture to fit the words. The classic example is XKCD's 'CorrectHorseBatteryStaple" https://xkcd.com/936/

About a year ago, I concocted a cute story that linked to a password, shared the story and password with some of my coworkers. They still seem to know it. We have decent memories - just not for random strings; there needs to be a story.

Oh, this is probably obvious, but do NOT use that xkcd password... :-)