Brownian

/**
 * Brownian motion.
 *
 * Recording random movement as a continuous line.
 */

const int num = 2000;
int range = 6;

float ax[num] = {0};
float ay[num] = {0};

void setup()
{
  size(640, 360);
  for (int i = 0; i < num; i++) {
    ax[i] = width/2;
    ay[i] = height/2;
  }
  frameRate(30);
}

void draw()
{
  background(51);

  // Shift all elements 1 place to the left
  for (int i = 1; i < num; i++) {
    ax[i-1] = ax[i];
    ay[i-1] = ay[i];
  }

  // Put a new value at the end of the array
  ax[num-1] += random(-range, range);
  ay[num-1] += random(-range, range);

  // Constrain all points to the screen
  ax[num-1] = constrain(ax[num-1], 0, width);
  ay[num-1] = constrain(ay[num-1], 0, height);

  // Draw a line connecting the points
  for (int i = 1; i < num; i++) {
    float val = float(i)/num * 204.0 + 51;
    stroke(val);
    line(ax[i-1], ay[i-1], ax[i], ay[i]);
  }
}