This is Garth Callaghan. He's been diagnosed with cancer three times in the last two years. He has about an 8% chance of surviving another five years.
He worked in a sales job when his daughter Emma was young. He couldn't see her a lot, so he wrote napkin notes for her lunch box.
The odds of his seeing her graduate from high school are very low.
So he's written a LOT of notes.
Other parents have been inspired by his idea.
One wrote to him: "This is brilliant! As a mom who travels weekly for my job, I'm finding it difficult to stay connected and ways to prove that she's still my #1 priority. I'm stealing your idea, in my own way of course."
He tells BuzzFeed: "I just want parents to be able to take that extra step in the morning and realize how much impact this action has."