Fig. 1. Fractal structures lie on a spectrum from monofractal to multifractal; these changes are represented as the width of the singularity spectrum. A multifractal system leads to a wide singularity spectrum (A ). As the system becomes less multifractal (more monofractal) the width narrows (B ). Because of numerical errors, very narrow distributions may give rise only to short line segments (C ). The spectral parameters h^m  (maximal Hölder exponent) and WHH  (width-at-half-height) are indicated for the most multifractal case (A ).