- 1). Turn your paper so that it points at you like a diamond. Make two valley folds between each pair of opposite corners. Make another valley fold so that the top corner touches the center where the first two folds intersect. Unfold that crease and make another valley fold so that the top corner touches the crease from the last fold.
- 2). Make a mountain fold so that the bottom corner touches the crease from the most recent fold on the other side. Unfold that crease and flip the paper over so that the top corner points toward you. Mountain-fold the top quarter of the paper that it points away from you, so that the tip of it touches the flat edge on the opposite side.
- 3). Find the hidden double fold at the flat top of the paper. Fold both sides up so that this double fold becomes four layers deep. Then unfold the paper back to where it was at the end of Step 1. Notice that the paper has five sides now and that the top is the smallest side. Think of the smallest side as side 1, and number the others 2, 3, 4 and 5, clockwise.
- 4). Fold sides 2 and 5 so that the top two corners, on either end of side 1, touch the top of the small triangle at the center, near the top of the paper. Notice that there are now two rectangles on the left and right of the paper, converging at the top, having the color of the opposite side of the paper.
- 5). Make two vertical mountain folds on either side of the vertical center line. The width between these two new folds and the center line should be the same as the two colored rectangles just mentioned. Try not to crease these new folds within the five horizontal center lines. Fold the top corner down along the top horizontal line, which is a valley fold. Crease this new downward-pointing triangle with mountain folds so that the creases run from the top corners to the center of the outermost vertical lines.
- 6). Mountain-fold the downward-pointing triangle so that it points up again. The newest crease should run between the end points of the creases made at the end of Step 5. The top corner should point slightly above the flat edge. Use the creases from the end of Step 5 to collapse this newest fold inward.
- 7). Rotate the paper so that the bottom corner points upward. Repeat Steps 5 and 6 on the new top corner, making the paper symmetrical. Make a vertical valley fold in between the two leftmost vertical creases so that the newest crease lies an equal distance from the other two. Fold the leftmost crease inward, then the center crease, to finish your origami submarine.
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