irregular curves are commonly called French curves.
These curves have no constant radii.
A radius curve is composed of a radius and tangent.
The radius on these curves is constant and ranges from 3 ft to 200 ft.
These curves are commonly used in highway drafting.
In addition to these two kinds of curves,
there are available ships curves.
The curve in a set of ships curves become progressively larger and,
like French curves, have no constant radii.
They are used for layout and development of ships; hulls.
Flexible curves are also available that allow you to adjust to a desired curve.