An idea that started in a Greenwich backyard has now turned into a series of children's books.

Steve Simmons and his son, Cliff, watched small creatures like butterflies, bumblebees and squirrels.

The duo decided to write a book about them, which turned into a series of books.

The series evolved into writing about bigger earth creatures like elephants, giraffes and monkeys.

The father and son duo's latest idea is based on sea animals and where ocean creatures go to sleep at night.

“We are thinking about the next creature we might want to focus on, or maybe a different theme but it’s been a great experience working with my son creatively on this,” Simmons said. “And we are very excited about Where Do Ocean Creatures Sleep at Night.

The Where do Ocean Creatures Sleep Night book will be released on April 16 in honor of Earth Month.

You can click here to find out how to purchase any of their books.