Quote from : Endless Summer Book

A smaller rocket cut across the sky, trailing smoke. It exploded in a red heart. "Awwwww!" said the crowd. "Upside down," said Sean. The heart was, indeed, upside down. It grew and grew, upside down, until it's lights trailed and faded. A bigger rocket exploded in bright golden sparks, and then came another red heart. "Upside down," said all the boys. Three explosions layered on top of one another, gold, blue, pink. Then still another red heart exploded, growing and growing before it faded. "Upside down," said everyone in the boat but me. My own heart expanded for Adam. I whispered, "I know what he meant.