This is a beautiful and surprisingly deep picture book, despite its lack of written words. At first glance the illustrations  appear simple, but when one takes the time to slow down and unpack them, they are profoundly deep. The lack of written words makes this book applicable to all ages, languages and open to a range of interpretations. 

The detail of the illustrations sharply focuses on the facial expressions of the two boys and their connection with each other. The largely white background of the illustrations allows this story to take place in any town, city or country and resonate with any reader. The use of sparing watercolour (yellow when things are positive and purple when things are negative) brings strong emotion and feeling to the story without feeling forced or laboured. 

In the book, the two boys discover that their charcoal-drawn lines can be picked up like a rope and can be joined together. Before long, conflict starts between the two boys and leads to a chasm opening between them. The boys need to work together to resolve their conflict and to bridge the divide. 

There is a lot of scope for a teacher or caring adult to ask curious questions to their children and allow them to come up with what they think is happening in each page (and what gives them this idea) and how the situation might be resolved. This story has a strong message of friendship and healing through conflict.