From the dynamic, dream team of Jon Klassen and Mac Barnett comes the final instalment in the hilarious shape trilogy

Triangle and Square are visiting Circle, who lives at the waterfall. When they play hide-and-seek, Circle tells the friends the one rule: not to go behind the falling water.

But after she closes her eyes to count to ten, of course that's exactly where Triangle goes. Will Circle find Triangle? And what OTHER shapes might be lurking back there?

• This masterful and much anticipated conclusion to the SHAPE trilogy brings Triangle and Square full circle. 
• Jon Klassen's HAT trilogy has sold 1.9 million copies to date. This Is Not My Hat is currently the only book to win both the Kate Greenaway and Caldecott Medal. 
• What Mac and Jon do so cleverly in their books is to ask questions of the child reader, encouraging their engagement with the story beyond the page