What was the original 'failed' adhesive that led to the invention of Post-it Notes described as?

Many revolutionary products we use daily were discovered by accident. Post-it Notes, now a staple in offices worldwide, have a fascinating origin story that demonstrates how consumer feedback and corporate innovation can transform a failed experiment into a billion-dollar product line. This trivia explores the surprising discovery behind one of 3M's most successful products and how it revolutionized workplace communication and organization.

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An adhesive that was 'too weak' and wouldn't stick permanently
An adhesive that was 'too strong' and damaged paper when removed
A waterproof coating that unexpectedly became sticky when dried
A transparent glue that yellowed over time creating the distinctive color