Self-parallel Spirals
The Archimedean spiral is often called a spiral with constant distance between its successive coils. Although this property is approximately true for the outer coils of the spiral, it is nowhere the case exactly, and near the center it is obviously wrong. However, there is a spiral which has exactly the geometric property of constant distance between successive coils in the sense of parallel curves, the involute of a circle .
Read more about this topic: Parallel Curve