Patterns in Ammonites

The spiral that occurs in the shape of an ancient ammonite shell is identified as the Golden Spiral. This spiral can be represented by the Fibonacci sequence. Since this spiral relates to the Fibonacci sequence, it is categorized as a Fibonacci pattern.

​

The pattern the ammonite shell represents the rule that after every quarter of a turn (90°) the shell extends its radius to the next number of the Fibonacci sequence. For example, if the radius at one point of the ammonite shell is the number 34, which is a Fibonacci number, then the radius of the shell 90° away from that point will be close to the next Fibonacci number, which is 55.