Ball Bouncing off Walls

int posX = 0;

int posY = 0;

int speedY= 5;

int speedX = 2;

​

void setup() {

  size(500, 500);

}

​

void draw() {

  background(0);

​

  posX = posX + speedX;

  posY = posY + speedY;

​

  if (posX > width) {

    speedX = speedX* -1;

  }

​

  if (posX < 0) {

    speedX = speedX* -1;

  }

​

  if (posY > height) {

    speedY= speedY* -1;

  }

  if (posY < 0) {

    speedY= speedY*-1;

  }

  ellipse(posX, posY, 50, 50);

}