Bird Base
Traditional:
This base is the starting position for countless models, which range from the simple to extremely complex.
Description:
A kite shape with the tail end comprising 4 points that meet at the tip of the tail: 1 at the front layer, 1 at the back layer, and 1 on either side in the middle layer.
Method:
1. Begin with a Preliminary base, colour side out and the four points down.
You have two main layers to the model, each consisting of two single layers and 2 inner layers on each side.
Label the points A to D starting at the top(the middle of the original square) in a clockwise direction.
2. Working with the top main layer of the model, valley fold line BC (2 raw edges) to lie along the centre line of the model (AC).
3. Repeat Step 2 with the left hand side of the model.
You now have 2 triangular flaps that meet at the centre line, AC, with their right angles next to each other.
Let the line running horizontally from left to right across the top edge of the triangular flaps formed in steps 2 and 3 be named EF: E is the point at the left, and F is the point at the right of that line.
4. Valley fold along line EF, so that point A is now lying on top of the model, along the centre line of the model.
5. Crease all flaps firmly and unfold back to Step 1.
6. Lift the bottom corner (point B) top single layer only, and valley fold upwards on line EF.
While doing this the raw edges will begin to come into the centre to lie along the centre line of the model.
Allow this to happen, the bottom halves will fold in on the pre-creased diagonal valley folds; while the top halves will meet resistance on diagonal mountain folds. Overcome this resistance and convert them to valley folds.
7. When the bottom corner has been lifted all the way up to lie flat on the table, the raw edges will meet along the centre line.
8. Turn the model over and repeat Steps 2-7 on the other side.
9. You should now have a tall, thin diamond that has 2 points at top (one lying on top of the other); and 2 at the bottom (lying next to each other).
There is a smaller point (The centre of the original square) between the front and back flap.
10. Bring the top front point down in front of the model, valley folding along line EF.
11. Bring the top back point down to the back of the model, valley folding along line EF.
This is the usual way (points down) to orientate the bird base. Unsurprisingly with the points left up, as at the end of Step 9, it is known as a "points up" Bird Base.
Stretched Bird Base
This is a variant of the base which is sometimes met with.
1. Start with a "points down" Bird Base and rotate it 180 degrees so that the 4 points are pointing upwards.
2. Take hold of the 2 inner points, gripping all 4 layers of paper together between the forefinger and thumb of each hand, pick the paper up off the table and start to pull your hands apart. This is the "stretching" part.
3. You will meet resistance. Continue pulling your hands apart until the paper "pops" then continue until you have a single straight mountain fold across the paper, from the left hand corner to the right.
4. Slide your thumb and forfinger in to the centre and gently flatten the isoceles triangles that are starting to form at the front and back. Try to flatten these triangles symmetrically.
5. The paper should now lie flat. It looks a bit like a long canoe sailing behind a mountain.