About a decade ago, Lawson was at a beach in Virginia watching his kids build castles right next to the waves. 

" I kept trying to get them to come back because I thought it was a terrible idea, " he remarked. He wanted them to build their sandcastles closer to the dunes (沙丘). But they found it more exciting to build right where the waves hit, seeing their sandcastles get destroyed, and then rebuilding them with whatever debris (残骸) washed up from the ocean. "It seemed so symbolic, somehow, of how life works more than just building your perfect sandcastles, " said Lawson. When he decided to turn that sunny day into a children's book, the idea came to just use pictures. "It seemed like it would work beautifully without words," he said.

A Day for Sandcastles is illustrated (加插图) by Qin Leng. It's the second wordless picture book for Lawson and Leng since 2021's Over the Shop. Leng's illustrations stay pretty true to real life. Three siblings spend the day building sandcastles and watching them get destroyed by a flying hat. "To me it's a celebration of childhood and the simple joys of life. These are the things I like to capture (捕捉)," said Leng.

Leng spent part of her childhood in France, and she was inspired by European comic books "What I love to do when I illustrate a picture book is add side stories to the main storyline. I always think about the readers and the longevity（持久） of the book, and I want them to be able to discover something new every time they revisit the book, " Leng explained.

At the end of the day, the sleepy-eyed kids pile into the bus that will take them home. "Those last pages are some of my favorite. They capture that feeling like at the end of the day on the beach, when it's getting dark and you feel completely exhausted," Lawson said. It must be a universal childhood feeling: happy with sand, sticky from the salt, hot from the sun, and ready to fall asleep the moment you get into the car.