Exactly solvable sandpile with fractal avalanching

A simple one-dimensional sandpile model is constructed which possesses exac t analytical solvability while displaying both scale-free behavior and frac tal properties. The sandpile grows by avalanching on all scales, yet its sh ape and energy content are described by a simple, continuous (but nowhere d ifferentiable) analytical formula. The avalanche energy distribution and th e avalanche time series are both pou er lows with index -1 (''1/f spectra'' ). [S1063-651X(99)00306-2].