A simple artistic mountainscape is produced by plotting several cosine curves generated with constrained random parameters (i.e. amplitude, frequency, phase, offset). Then noise is added to the curve and smoothed out by a moving average to give the treeline a realistic profile. You can change the number of mountain ridges and the color scheme.
This project was inspired by http://blog.craftzine.com/archive/2011/03/gradient_color_block _mountain.html.