float px, py;
float v1x, v2x, v3x;
float v1y, v2y, v3y;


void setup() {
  fullScreen();
  background(0);

  v1x = width/2;
  v2x = width/6;
  v3x = 5*width/6;

  v1y = 50;
  v2y = v3y = height-50;

  fill(125, 255, 0);
  ellipse(v1x, v1y, 5, 5);
  ellipse(v2x, v2y, 5, 5);
  ellipse(v3x, v3y, 5, 5);

  px = v1x;
  py = v1y;
}

void draw() {

  float tempvx, tempvy;

  for(int i = 0; i < 50; ++i) {
    int v = (int)random(3) + 1;
    switch(v) {
      case 1: tempvx = v1x; tempvy = v1y; break;
      case 2: tempvx = v2x; tempvy = v2y; break;
      default: tempvx = v3x; tempvy = v3y;
    }

    px = (px + tempvx)/2;
    py = (py + tempvy)/2;

    ellipse(px, py, 5, 5);
  }
}