private void monteCarlo() {
        //WRITE YOUR CODE TO UPDATE EVERYTHING HERE
        switch (this.last_input) {//handle user input
            case W:
                this.sensor.stopFire();
                robot.point.y -= 20;
                moveParticles(0, -20);
                moveEstimate();
                break;
            case A:
                this.sensor.stopFire();
                robot.point.x -= 20;
                moveParticles(-20, 0);
                moveEstimate();
                break;
            case S:
                this.sensor.stopFire();
                this.robot.point.y += 20;
                moveParticles(0, 20);
                moveEstimate();
                break;
            case D:
                this.sensor.stopFire();
                this.robot.point.x += 20;
                moveParticles(20, 0);
                moveEstimate();
                break;
            case UP:
                this.sensor.stopFire();
                this.sensor.fireNorth();
                comparePointsY(calculateStandardDeviationY(robot.point.y), robot.point.y);
                moveEstimate();
                break;
            case DOWN:
                this.sensor.stopFire();
                this.sensor.fireSouth();
                comparePointsY(calculateStandardDeviationY(robot.point.y), robot.point.y);
                moveEstimate();
                break;
            case LEFT:
                this.sensor.stopFire();
                this.sensor.fireWest();
                comparePointsX(calculateStandardDeviationX(robot.point.x), robot.point.x);
                moveEstimate();
                break;
            case RIGHT:
                this.sensor.stopFire();
                this.sensor.fireEast();
                comparePointsX(calculateStandardDeviationX(robot.point.x), robot.point.x);
                moveEstimate();
                break;
        }
        //update particles

    }