If you're a picture book maker with words and pictures, you probably have some experience of 'the missing link'.
What is the missing link? It's that sticking point that's stuck in your story - where something is wrong and you don't know how to fix it. Believe me, I've been there.
I remember when I was taking a picture book class from Maurice Sendak at Parsons, he had suffered from 'the missing link'. There was one page in 'Outside Over There' where something was wrong. It puzzled him for weeks until he finally discovered the art of the ice babies page needed to be changed... and then things worked.
One mistake at a time - fixing up a page of art or changing the ending of the words or the dozen other changes one makes in a book are all part of the fun. I'm totally bored with crosswords or other puzzles, but I'm as stubborn as a donkey when it comes to trying to solve 'the missing link'