Gather paper, scissors, a pencil, a ruler, a pin, and a straw or wooden skewer
Cut a square from the paper
Draw diagonal lines from each corner toward the center, stopping before the center
Cut along each diagonal line
Fold every other corner toward the center
Push the pin through the folded corners and the center
Attach the pin to the pencil, straw, or skewer
Make sure the pinwheel can spin freely
Blow on it or place it in the wind to test it