Processing Walk

class Walker {
  int x;
  int y;
  
  Walker () {
    x = width / 2;
    y = height / 2;
  }
  
  void display() {
    stroke(30);
    point(x,y);
  }
  
  void step() {
    int choice = int(random(4));
    int stepAmount = 4;
    
    if (choice == 0) {
      x += stepAmount; 
    } else if (choice == 1) {
      x -= stepAmount; 
    } else if (choice == 2) {
      y += stepAmount;
    } else {
      y -= stepAmount;
    }
  }
}

Walker w;

void setup() {
  size(640,360);
  w = new Walker();
  background(255,255,255);
}

void draw() {
  w.step();
  w.display();
}