function mountain(element, options) {
    options = options || {};
    var ox = options.ox || 3;
    var oy = options.oy || 6;
    var mw = options.mw || ox * 2;
    var mh = options.mh || ox * 2;
    var chance = options.chance || .3;
    var index = options.index || 0;
    var gradient_steps = options.gradient_steps || 100;
    var gradient_colors = (
        options.gradient_colors ||
        [[0, 0, 0, 0], [1, 255, 255, 255]]);
    if ('gradient_animate' in options)
        var gradient_animate = options.gradient_animate;
    else
        var gradient_animate = false;
    if ('gradient_background' in options)
        var gradient_background = options.gradient_background;
    else
        var gradient_background = true;
    if ('gradient_repeat' in options)
        var gradient_repeat = options.gradient_repeat;
    else
        var gradient_repeat = false;

    function bounds(element) {
        var top = 0, left = 0, e = element;
        do {
            top += element.offsetTop || 0;
            left += element.offsetLeft || 0;
            element = element.offsetParent;
        } while (element);
        return {
            'left': left,
            'top': top,
            'width': e.clientWidth,
            'height': e.clientHeight
        };
    }

    function choice(sequence) {
        return sequence[Math.round((sequence.length - 1) * Math.random())];
    }

    function random_range(min, max) {
        return Math.round((max - min) * Math.random() + min);
    }

    function gradient(resolution, stops) {
        var colors = [];
        for (var i = 0; i < stops.length - 1; i++) {
            var r = resolution * stops[i + 1][0] - resolution * stops[i][0];
            for (var n = 0; n < r + 1; n++) {
                var c = [];
                for (var m = 1; m < 4; m++) {
                    c.push(parseInt((stops[i + 1][m] - stops[i][m]) * (n / r) + stops[i][m]));
                }
                colors.push('rgb(' + c[0] + ',' + c[1] + ',' + c[2] + ')');
            }
        }
        return colors;
    }
    
    function raise(step) {
        var e, l, t, w, h, d, s = document.createElement('div');
        s.style.top = (parseInt(step.style.top) || 0) - oy + 'px';

        function mke(l, t, w, h) {
            e = document.createElement('div');
            e.style.left = l + 'px';
            e.style.top = t + 'px';
            e.style.width = w + 'px';
            e.style.height = h + 'px';
            e.style.zIndex = index;
            s.appendChild(e);
        }

        for (var i = 0; i < step.childNodes.length; i++) {
            l = parseInt(step.childNodes[i].style.left) + ox;
            t = parseInt(step.childNodes[i].style.top) + ox;
            w = parseInt(step.childNodes[i].style.width) - (ox * 2);
            h = parseInt(step.childNodes[i].style.height) - (ox * 2);
            if (w < mw || h < mh) continue;
            if (Math.random() < chance) {
                if (w / h > 1) {
                    d = true;
                } else {
                    d = false;
                }
                //d = choice([true, false]);
                if (d) {
                    var w2 = choice([
                        random_range(0, Math.round(w * .33)),
                        random_range(Math.round(w * .66), w)]);
                    mke(l, t, w2, h);
                    mke(l + w2, t, w - w2, h);
                } else {
                    var h2 = choice([
                        random_range(0, Math.round(h * .33)),
                        random_range(Math.round(h * .66), h)]);
                    mke(l, t, w, h2);
                    mke(l, t + h2, w, h - h2);
                }
            } else {
                mke(l, t, w, h);
            }
        }
        chance = chance * 0.95;
        index++;
        if (e) {
            step.parentNode.appendChild(s);
            return s;
        }
    }

    // main

    var b = bounds(element);

    var m = document.createElement('div');
    m.className = 'mountain';
    document.body.appendChild(m);
    m.style.left = b.left + 'px';
    m.style.top = b.top + 'px';
    m.style.width = b.width + 'px';
    m.style.height = b.height + 'px';

    var s = document.createElement('div');
    var e = document.createElement('div');
    e.style.left = 0 + 'px';
    e.style.top = 0 + 'px';
    e.style.width = b.width + 'px';
    e.style.height = b.height + 'px';
    s.appendChild(e);
    m.appendChild(s);

    var gradient_colors_shade = [];
    for (var i = 0; i < gradient_colors.length; i++) {
        var clr = gradient_colors[i];
        var r = clr[1] - 40, g = clr[2] - 40, b = clr[3] - 40;
        if (r < 0) r = 0; if (g < 0) g = 0; if (b < 0) b = 0;
        gradient_colors_shade.push([clr[0], r, g, b]);
    }
    var g1 = gradient(gradient_steps, gradient_colors);
    var g2 = gradient(gradient_steps, gradient_colors_shade);

    var css = [
        '.mountain {position:absolute}',
        '.mountain div {position:absolute}',
        '.mountain div div {position:absolute}'
    ];
    for (var i = 0; i < gradient_steps; i++) {
        css.push(
            '.mountain .c' + i +
            ' div{background-color:' + g1[i] + ';' +
            'border-right:3px solid ' + g2[i] + '}');
    }

    var style = document.createElement('style');
    style.setAttribute('type', 'text/css');
    style.appendChild(document.createTextNode(css.join('\n')));

    document.body.appendChild(style);

    var index = 0;
    function _raise() {
        if (s) {
            s = raise(s);
            if (s) {
                if (!gradient_animate) {
                    if (gradient_repeat)
                        s.className = 'c' + (index % gradient_steps);
                    else
                        s.className = 'c' + (
                            index < gradient_steps ? index : gradient_steps - 1);
                    index++;
                }
                setTimeout(_raise, 30);
            }
        }
    };
    _raise();

    if (gradient_animate) {
        var index = 0;
        setInterval(function() {
                for (var i = 0; i < m.childNodes.length; i++) {
                    m.childNodes[i].className = 'c' + ((i + index) % gradient_steps);
                }
                if (gradient_background) {
                    document.body.style.backgroundColor = g2[(index % gradient_steps)];
                }
                index++;
            }, 30);
    }
}