  Finite elements of higher continuity, say conforming in $H^2$ instead of
$H^1$, require a mapping from reference cells to mesh cells which is
continuously differentiable across cell interfaces. In this article, we propose
an algorithm to obtain such mappings given a topologically regular mesh in the
standard format of vertex coordinates and a description of the boundary. A
variant of the algorithm with orthogonal edges in each vertex is proposed. We
introduce necessary modifications in the case of adaptive mesh refinement with
nonconforming edges. Furthermore, we discuss efficient storage of the necessary
data.
