Triangle is a breath of fresh air in the picture book world—no saccharine lessons, no over-explaining, just shapes being sneaky and a story that trusts kids to figure things out. Barnett and Klassen's collaboration is sharp and visually striking, with a dry wit that appeals to parents reading aloud.

It's not for every kid. Some will want more warmth, more plot, more resolution. But for families who appreciate clever, minimalist storytelling, this is a gem. The fact that it spawned an Apple TV+ series (Shape Island) speaks to its appeal, though the book itself is a quick, quiet experience.

Solid pick for bedtime or classroom read-alouds, especially if you want to spark a conversation about friendship, trust, and what happens when your sneaky plan backfires.