The egg of Columbus is an apocryphal tale about ideas that seem trivial after the fact. The story originates from the book “History of the New World” by Girolamo Benzoni, who wrote that Columbus, upon upon being told that his journey to the West Indies was unremarkable and that Spain “would not have been devoid of a man who would have attempted the same” had he not undertaken the journey, replied “Gentlemen, I will lay a wager with any of you, that you will not make this egg stand up as I will, naked and without anything at all.” They all tried, and no one succeeded in making it stand up. When the egg came round to the hands of Columbus, by beating it down on the table he fixed it, having thus crushed a little of one end”
Almost every business management book I’ve read has felt like something obvious, but I’m not quite sure how difficult they may have been for others to have written.
A more interesting class of these problems are magician’s tricks, which once explained are almost painfully obvious. Perhaps this is why the class of magicians swear themselves to secrecy? Once the trick is revealed, there’s no more magic, so to keep the illusion, one doesn’t reveal them.