J.k. Rowling said this quote
“ He read the letter again, but could not take in any more meaning than he had done the first time and was reduced to staring at the handwriting itself. She had made her g's the same way he did : he searched through the letter for every one of them, and each felt like a friendly little wave glimpsed from behind a veil. The letter was an incredible treasure, proof that Lily Potter had lived, really lived, that her warm hand had once moved across this parchment, tracing ink into these letters, these words, words about him, Harry, her son. ”