The Shape Trilogy by Mac Barnett and Jon Klassen is a charming, visually engaging collection of three picture books featuring the characters Triangle, Square, and Circle. Each book focuses on a different shape character, exploring themes of friendship, problem-solving, and self-discovery through humor and simple yet expressive illustrations. Here’s a brief look at each book in the set:

1. Triangle
   This story follows Triangle, a mischievous shape who sets out to play a trick on his friend Square. Triangle’s playful journey through a world of shapes introduces readers to a fun, unexpected story of friendship, with Triangle’s cheeky personality adding plenty of laughs.

2. Square
   Square is a hardworking, diligent shape who spends his days stacking square blocks. One day, his friend Circle asks him to make a perfect circle sculpture, setting off a tale about creativity, self-doubt, and the nature of art. Through this story, readers see Square’s persistence and get a gentle message about finding beauty in imperfection.

3. Circle
   In the final book, Circle leads her friends Triangle and Square on a quest that tests their bravery. When Triangle breaks the only rule (to not go into a dark cave), the trio faces their fears in an exploration of trust, courage, and friendship. Circle’s caring nature and her resolve make for a heartwarming conclusion to the trilogy.