From a story by me in Glimmer Train, called "The Mailman"

I love you.

It was nice to read that, nice to have it in black and white on a piece of paper she could look at again and again.  It was only later, after a couple of weeks, she noticed the words written there growing fainter and fainter, and finally disappearing, as though they had been written with smoke.

I love you.

I  o e yo

o     o

     o

Then the paper itself would crumble – ashes. 

Nothing lasts.