What are the pictures shiobhan shows Christopher and why does he need them?

Siobhan is Christopher's friend of eight years and a member of the staff at his school, where he studies with other children with learning difficulties. To help Christopher understand human emotion, she draws faces for him so that he can identify that a smile means happy, a frown means angry and so on. It is Siobhan who sets the assignment that propels Christopher to write his novel, and she gives him writing tips throughout. She is very patient with Christopher and encourages his writing.