"puzzlewocky.com/brain-teasers/" - I clicked on it, and was presented with "Each Shuffle of a Deck of Cards is Probably Unique in History", PROBABLY unique, not IS unique.
BTW check out this from Lily Serna on why you don't need 183 at a party in order to have a 50% chance of having the same birthday as someone else there - in fact you only need 23 people. Not 183, 23. Now apply the same principle to the card shuffles https://www.abc.net.au/education/catalyst-probability-and-the-birthday-paradox/13605458
