1-Start with a circle.Add a small crescent as shown.

2-Draw a circle inside the previous one. It should be off center in the lower left area.

3-Connect that smaller circle to the outer circle with a curve.Erase dotted area.

4-Add a smaller circle inside the middle circle as shown.

5-Connect small circle and middle circle with a curved line.

6-Add another small circle as shown. Erase dotted area.

7-Draw one last tiny circle that touches the top of the last circle.Erase dotted area.

8-Add a rim to the front of the shell as shown.

9-Add body, head and eyestalks on the right and triangle tail on the left.
