while (true){

    let r1 = random(0, 10);

    let p = r1;

    let r2 = random(0, 10);

    if (r2 < p){

      return r1;

    }

  }

}

​

class Walker {

  constructor(){

    this.x = width/2;

    this.y = height/2;

  }

  display(){

    stroke(0);

    let wx = constrain(this.x, 0, width)

    let wy = constrain(this.y, 0, height)

    ellipse(wx, wy, 10, 10);

  }

  step(){

    let stepsize = monteCarlo()

    let stepx = random(-stepsize, stepsize)

    let stepy = random(-stepsize, stepsize)

    this.x += stepx;

    this.y += stepy;

  }

}