renatolrr_cicreart2017/ejemplos/Walker_multiples/Walker_multiples.pde
class Walker {
  int x,y;
  Walker() {
    x = width/2;
    y = height/2;
  }
  void render() {
    stroke(0);
    point(x,y);
  }
  void step() {
    int choice = int(random(4));
    if (choice == 0) {
      x++;
    } else if (choice == 1) {
      x--;
    } else if (choice == 2) {
      y++;
    } else {
      y--;
    }
    x = constrain(x,0,width-1);
    y = constrain(y,0,height-1);
  }
}
Walker w;
void setup() {
  size(640,360);
  background(255);
  w = new Walker();
}
void draw() {
  w.step();
  w.render();
}