Random Walk

The random walk is a mathematical model of a path of random steps. It is used to describe many processes in nature, like the path of a foraging animal or the motion of a gas particle. Our first assignment for Nature of Code was to construct a program in Processing that demonstrates this behavior.

For my program, I altered Dan Shiffman’s random walk example to have multiple walker objects (i.e. many random walk paths are generated simultaneously from different origins). At each point along the path, Processing draws a new arc. There are exactly 51 walker objects, since the red value of the arc color increments by 5 with each iteration and the maximum red value is 255.

Here’s the code for main program:

[code lang="java"]Walker[] w;

void setup() {
  background(3, 57, 90);
  //51 walker objects - red value increases by 5 until it hits 255
  w = new Walker[51];
  for(int i=0; i < w.length; i++)
    w[i] = new Walker(i*5, i*10, i+height/2);

void draw() {
  for(int i=0; i < w.length; i++)

This is the code for the walker object:

[code lang="java"]
class Walker {
  int x,y;
  int r;

  Walker(int r_, int x_, int y_) 
    x = x_;
    y = y_;
    r = r_;

  void render() 
   fill(r, 120, 0);
   arc(x, y, 10, 10, PI, 2*PI);

  // Randomly move up, down, left, right, or stay in one place
  void walk() 
    int vx = int(random(3))-1;
    int vy = int(random(3))-1;
    x += vx*5;
    y += vy*8;
    x = constrain(x,0,width-1);
    y = constrain(y,0,height-1);