My cousin and his wife lost their second baby girl at 26 weeks, Millie Violet. For at least a few years afterwards they would sign their cards with all their names plus "Millie in the Moon". I thought it was a really sweet way to remember their precious girl born too early, but i must admit that was the first time I'd ever encountered this. Im not sure if they still do it, but they lost Millie about 5 years ago now.