What was the original 'failed' invention that eventually led to the creation of Post-it Notes?

The journey from invention to iconic product often involves unexpected twists. The Post-it Note represents one of the most fascinating product design stories in retail history - a seemingly simple item that revolutionized how we communicate and organize information. Behind this ubiquitous office supply lies a tale of accidental discovery, persistence, and innovative marketing that transformed an initial 'failure' into a global success.

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A super-strong adhesive that wouldn't come off
A weak, pressure-sensitive adhesive that could be repositioned
A heat-activated glue for bookbinding
A waterproof paper coating that accidentally became sticky