The Chambered Nautilus(Nautilus pompilius) is one of the oldest of the cephalopods.a group that includes the octopus and squid.It is highly valued for its symmetric shell.which forms a logarithmic spiral in cross section.The Nautilus is native to the Indian and Paciflc Oceans.

Crease the diagonal of the square and make a pinch mark along the left side halfway up.

Fold the top right corner down to the pinch mark you just made.

Unfold

Fold the top edge down to lie along the diagonal.

Fold the bottom right corner up to touch the intersection of the last two creases.

Fold the corner behind along the diagonal of the square.

Like this.Turn the papaer over.

Fold the bottom left corner up to match the one behind and unfold.

9.Fold the edge up to touch the crease you just made.10.Fold up on the existing crease.11. Turn the papaer over.12.Unfold this flap and repeat steps9-10  13. Fold and unfold.

Fold the left point over to the right so that the top edges of the point are aligned.

Fold the point back to the left so that the bottom edges of the point are aligned.

Repeat steps 14-15.Note the location of the valley fold.

Continue pleating as in steps 14-15 until you get to the end of the colored part of the point(for a total of about 12 or 13 pleats).

Like this.Unfold to step 13.

Using the existing creases.crimp both of the bottom edges so that the paper colls up again.The colored flap on the front(and the corresponding one on the back)should not be trapped in the pleats of the white layer;see step 20 for the crease pattern.

This shows the crease pattern for step19.

Unfold again to step 13 and open the model out flat

Using the exsiting creases as guides.crimp the point downward.folding it back and forth(push arrows are shown only for the first crimp),

Like this.Fold the paper in half carefully (because of the many layers the model is quite thick).Rotate the model 90 degrees counterclockwise.

Carefully pull out the top of the protruding point and pivot it downward.taking point A as the axis of rotation.This has the effect of restoring a crimp we made in step 20.

Like this.Now,carefully grasp that crimp and pull it out.again pivoting around point A;the result is to restore the next crimp.

Continue pulling each crimp out and pivoting around point A.The paper remains locked together at point A at all crimps (except for an inevitable small amount of slippage).Continue until you've done them all(look ahead to step 27 to see what you're trying to accomplish).

The paper should be securely locked together at the center of the rotation.Reverse-fold the top corner.Mountain-fold the corners shown.Repeat behind.

Reverse-fold the corner back up.

Sink the hidden corner.

Fold the tip down.

Fold the point over and over and tuck it into the pocket.

Open out the shell and turn it over.

Now it is complated.