constructor() {

    this.x = width / 2;

    this.y = height / 2;

    this.history = [];

    // this.pos = createVector(width/2,height/2);

  }

​

  render() {

    stroke(0);

    point(this.x, this.y);

    for (let i = 0; i < this.history.length; i++) {

      point(this.history[i].x, this.history[i].y);

    }

  }

​

  step() {  

    let choice = floor(random(4));

    if (choice === 0) {

      this.x++;

    } else if (choice == 1) {

      this.x--;

    } else if (choice == 2) {

      this.y++;

    } else {

      this.y--;

    }

    this.x = constrain(this.x, 0, width - 1);

    this.y = constrain(this.y, 0, height - 1);

    for (let i = 0; i < this.history.length; i++) {

      this.history[i].x += 0.2;

    }

    let v = createVector(this.x, this.y);

    this.history.push(v);    

  }

}