Apple may be notoriously tight-lipped about what it's working on, but that's never stopped it from having just a little bit of fun with teasing what's to come. From subtle wordplay to carefully chosen imagery, Apple has a history of dropping hints and hiding details about its next announcement right on the invitations it sends out for each event.

We've collected most of Apple's invitations over the last decade to see just how those hints were hidden, where Apple left no hints at all, and just what it all might mean for the company's next event.