how do i get a amex black card
Centurion Card The Centurion Card is invitation-only after appropriate net worth, credit, and spending criteria are met.[3] American Express does not publicly disclose the requirements necessary for getting or keeping a card, except that the cardholder needs to have a substantial net worth, as well as having been a Platinum card holder.[3]
Punched card Charles Babbage proposed the use of "Number Cards", "pierced with certain holes and stand opposite levers connected with a set of figure wheels ... advanced they push in those levers opposite to which there are no holes on the card and thus transfer that number" in his description of the Calculating Engine's Store.[8]