He made this card for us at the end of last year. It sits atop my bookshelves just across from where I'm sitting. I often think how hard it must be for him to have two homes. I guess I only think that because I grew up in one, but if I had had two, then I would have got used to having two and having to make a card for each of my homes, just as Z has.
Inside the card, he has drawn these Ns and Zs in a circle. It's him referencing PJ referencing him. Last year or maybe it was the year before when Z was learning the alphabet, he said to PJ, "Ns and Zs come from the sky, Daddy." His allusion to the way lightning looks when it flashes from the clouds.
And here's this, PJ's poem about Z's language discovery in the sky: