Triangle by Mac Barnett and Jon Klassen

Walker Books, 2017. ISBN 9781406376678
(Age: 3-5) Warmly recommended. Board book, Shapes, Mathematics, Friendship. A hardcover book about triangles! Hmm. But the face made by the triangle on the front cover invites the reader to open up and look inside.
Triangle lives in his house, a triangle, and uses his door, a triangle. He walks to his friend's house, Square. To get there he walks past big triangles and little triangles, shapes that are not triangles at all, until he gets to Square's house. Here he plays a sneaky trick on his friend, and then is followed by Square all the way back home. Once back home, Square becomes stuck in Triangle's door, and so plays a sneaky trick on Triangle, blocking the light, knowing Triangle is afraid of the dark.
By the end of the story children will be laughing at the tricks the two shapes play on each other, they will know what makes a square and a triangle, and that one cannot fit into the other. They will also have realised that playing tricks on their friends is not quite the best way to treat friends.
The seemingly simple illustrations done in single bold colours will intrigue readers. Shapes are contained on each page, reinforcing the theme of the book, and the eyes peeing out from the shapes will entrance all readers, while the question on the last page will cause wonderment as the readers question what they have seen happen.
By the authors of Sam and Dave dig a hole, and Extra yarn, both Caldecott Honour Books.
Fran Knight