Solution to Challenge 1

Worked example: a simple fish from the fish base.

Method
1. Choose the subject. A fish has a body, a tail and (optionally) fins, so a base with a point at each end suits it.
2. Fold a fish base from a square, white side up. This gives a body with a long point at one end and a forked end at the other.
3. Narrow the head: make a small inside reverse fold on the long point, so it tilts down like a nose.
4. Shape the tail: fold the forked end's two points outward with a pair of small outside reverse folds to make a V-shaped tail.
5. Add fins: valley-fold one small flap on each side of the body outward.

Refining over three folds
- First fold: the nose is too thick and the tail uneven. Note which fold caused it.
- Second fold: crease more precisely and reduce the nose to one reverse fold.
- Third fold: remove any step that does not change the shape, and fold on the final paper.

Write the step list in the form: "1. Fold a fish base. 2. Inside reverse fold the nose. 3. ..." using the symbols from Origami and Paper Folding 2.

Checkpoint: someone else can fold your model from the step list alone and get the same shape.