Khan Academy
Khan Academy: Recognizing Shapes
Learn the names of different shapes and how to recognize them. [6:08]
Khan Academy
Khan Academy: Composing Shapes
Shows how shapes can be put together to make new shapes. [2:04]
Other
E Spark Learning: Composing Shapes Framing Video
Demonstrates how to put shapes together to make a new shape, e.g., two triangles to make a square, and asks students to do this on their own and record their ideas. [0:33]