The Greedy Triangle by Marilyn Burns

In this book, a triangle explores all the different things he can make as a triangle—a sailboat, a roof, a piece of pie. But he decides he is bored with being a triangle and goes to the shape shifter to get another side and become a quadrilateral! He explores all the things he can be as a square—a computer screen, a picture frame, a game square. Again, he gets bored and goes to the shape shifter to get another side. This continues until the shape is almost round and rolls away from all his friends. In the end, he decides he wants to go back to being himself, a triangle. When reading this book, have fun with children exploring all the different shapes but don’t worry about them remembering the names for all these shapes. Just use the terms naturally as they arise and the children will pick up some of the words the same way they build the rest of their vocabulary.
Art extensions.
Have children focus on one shape with different number of sides at the art table. You can put out straight edges (such as rulers) and tracing shapes to help them get started. One day have them focus on triangles—making 3-sided shapes of all different sizes and length of sides. They can create sailboats, buildings, ladders, or anything they can imagine using triangles. Another day, have children focus on quadrilaterals making windows, buildings, boxes, books, toys, or anything they can imagine. Continue with pentagons, 5 sided shapes.

the greedy triangle