1. Geometry Origami - Nightingale
What shape do we begin with?

2. Geometry Origami - Nightingale
Fold along the diagonal of the square, with the colored side out.
What shape do we have now?

3. Geometry Origami - Nightingale
At the right angle, pick up 1 layer of the paper. Fold it straight up so that the vertex sticks out about 1 inch above the hypoteneuse of the triangle.

4. Geometry Origami - Nightingale
What angles do you see? How can you prove their measure?
Do you see the white square?

5. Geometry Origami - Nightingale
In the white square, one of the diagonals already has a fold line. Fold along the other diagonal, colored side out.

6. Geometry Origami - Nightingale
You should now have 2 triangles. The smaller triangle is the bird’s head. Rotate the paper so the bird’s head is pointing left and the wings are pointing down.
What shapes do we have now? Can you prove it?

7. Geometry Origami - Nightingale
Starting with the 45° angle of the small triangle, draw a line from it to the hypoteneuse of the large triangle. This line should be neither parallel nor perpendicular to the sides of the large triangle.

8. Geometry Origami - Nightingale
At the bottom vertex of the large triangle, pick up 1 layer and fold on the line you drew. Now one of the bird’s wings is up.

9. Geometry Origami - Nightingale
Flip the paper over.

10. Geometry Origami - Nightingale
Fold the other wing up so that it lines up with the first wing.