Have you ever thought you invented something that later appeared to already exist?

So yeah, title explains it all I think.

Have you ever “invented” or thought of something new and original that you later found out to exist. Examples include words, phrases, song melodies, designs, etc etc.

Also to what extent do you think that you may have already been exposed to this item but had forgotten about it for a period before you “invented” it?

When I was younger I used to think of song melodies that I would later listen to on the radio. I used to think that people in the music business were spying on me in order to make music. Oh how foolish I were.