  A family of plane oriented continuous paths depending on a fixed real
positive number $R$ is considered. For any point $x$ on the path, the previous
points lie out of any circle of radius $R$ having at $x$ interior normal in a
suitable tangent cone to the path at $x$. These paths are locally descent
curves of a nested family sets of reach $R$. Avoiding any smoothness
requirements, we get angle estimate and not intersection property. Afterwards
we are able to estimate the lenght and detour of this curve.
