Invention #5 Post-it Note
Dr Spencer Silver and Art Fry are credited with inventing the Post-It note in 1968 which 3M sell millions of yearly. Spencer wanted an adhesive with “removability characteristics” whilst Art wanted to have a bookmark that would stay in place. These guys have actually made money from their creation, however they describe themselves as comfortably well off rather than wealthy. The Post-It note is proof that simple ideas are often the best.