\begin{definition}[Definition:Cornu Spiral]
The '''Cornu spiral''' is the locus $C$ of the equation expressed in intrinsic coordinates as:
:$s = a^2 \kappa$
where:
:$s$ denotes the length of arc at a point of $C$ from the origin
:$\kappa$ denotes the curvature of $C$ at that point.
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\end{definition}