Here's another beautiful program on Processing(processing.org) I made: a colorful mountain complex. To create the "mountain"-effect, I use the noise() function, which also creates a random curve to the mountains. However, unlike random(), it creates a smooth increment/decrement on numbers called Perlin noise instead of random numbers jumping up and down. 

This is the code:


float b = 0;
float c = 0;
 size(1000,200);//This sets the window's length and width


for(int i = 0; i < random(80,300); i++) {
  stroke(random(255),random(255),random(255),random(70,100));
  strokeWeight(2);
   for(int count = 0; count < width; count++) {
      b = noise(c) * 200;
      c = c + 0.01;
      line(count,200,count,b);
   }
   
}

Here are my results:

For more info on Perlin noise and noise() :

http://processing.org/reference/noise_.html
http://en.wikipedia.org/wiki/Perlin_noise