  Forced packing of a long metallic wire injected into a two-dimensional cavity
leads to crushed structures involving a hierarchical cascade of loops with
varying curvature radii. We study the distribution of elastic energy stored in
such systems from experiments, and high-resolution digital techniques. It is
found that the set where the elastic energy of curvature is concentrated has
dimension $D_\mathcal{S} = 1.0 \pm 0.1$, while the set where the mass is
distributed, has dimension $D =1.9 \pm 0.1$.
