- Picture Books
- Ages 3–7
- Comedy
Triangle
Book 1 of 3 in The Shape TrilogyView the full series
Part of the Mac Barnett universeOpen the collection
Triangle makes a long journey to Square's house with one purpose: to give Square the fright of his life. Mac Barnett and Jon Klassen's debut collaboration is deadpan perfection, slow, spare, and funnier the more you look at it.
- Best for3–7
- FormatPicture
- Length56 pp
- Read aloud~11 min
The vibe
What it’s like.
Style
- Repetitive
- Conversational
Tone
- Funny
- Whimsical
- Absurdist
- Suspenseful
Themes
Experience meters
What’s it about?
The story.
Triangle has a plan: he will sneak to Square's house in the mountain and scare him. He is very good at scaring. He walks. He walks. He reaches the mountain and descends into the cave where Square lives. He roars his most terrifying roar. And Square is not scared. At all. Mac Barnett's text is a masterclass in dry understatement, short sentences, long pauses, Triangle's unshakeable confidence in himself against all visual evidence to the contrary. Jon Klassen's flat shapes and expressionless faces do all the work the words leave undone. This is a book that reads one way the first time and differently on every reread as you notice more of what the pictures are quietly communicating. As funny for adults as for children, and funnier in proportion to how slowly you read it aloud. The first of three books following the same three shapes, it establishes the comic dynamic that the series builds on, Triangle as perpetual schemer, Square as oblivious foil.
Fit check
Right for your child?
Where it lands by age
- 1
- 3
- 5
- 7
- 9
- 11
- 13
- Best fit · 3–7
- Read aloud · 3–10
- Independent · 5–7
Prose load
Minimal
Visual support
Very high
Reluctant-reader friendly
Very
Read-aloud quality
Excellent
Works well for
- Reading aloud
- Reading together
- Gift-buying
- Reluctant readers
Nothing in the book is likely to concern most parents. Safe to recommend without preview.
Bedtime suitability
3 / 5 · Workable
Sensitive-child
4 / 5 · Good fit
Graphic intensity
1 / 5 · None
Best for
- Picture book adults love
- Dark humour
- Gift book
- Read aloud
- Caldecott honor
Avoid if
No common reasons to avoid this one — a rare clean sweep on the sensitivity flags.
In the classroom
How it works in school.
Barnett and Klassen's deadpan shape trilogy — funny read-alouds rich for inference and talk about friendship, trust and mischief.
A book children love that happens to support school — never a stand-in for the texts a class is taught with. Reviewed for the classroom · June 2026.
Why it lands
Why they love it.
Why kids love it
The specific delight is the unscared Square — Triangle walking and walking to scare Square, roaring his most terrifying roar, Square not scared at all, the trick rebounding the whole way home. The Shape Trilogy opener that rewards reading aloud slowly.
- Trickery and cleverness
- Having a nemesis
Why parents love it
The Mac Barnett / Jon Klassen debut collaboration — deadpan understatement, flat shapes and expressionless faces doing every emotional beat, the trilogy that's essentially a philosophical comedy about identity and trust. Funnier for adults than for children, and very funny for children.
- Shared humour
- Great writing
- Quick to read
- Beautiful illustrations
In the series
The Shape Trilogy.
3 books · open the series →
About the creators
About the creators.
If you liked this
Three ways out of this book.
If you liked this, try…
Lateral matches. Same shelf, different texture.
Come into this from…
Easier or preparing reads — perfect lead-ins.
Where to go next…
Escalation reads — a step up in scale, silliness, or stakes.
More like this…
Books that share themes and topics with this one.
Buy or borrow
Pick up a copy.
- Bookshop.org ↗
- Waterstones ↗
- Amazon UK ↗
- Hive ↗
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