int xLoc = 0;
int xVelocity = 2;
int rad = 20;
int radVel = 2;

void setup() {

  size(200,200);
  background(0);

}

void loop() {

  //framerate(10);

  //DRAWING CODE
  background(0);
  stroke(200);
  fill(100);
  ellipseMode(CENTER_DIAMETER);
  ellipse(xLoc,mouseY,rad,rad);

  //LOGIC
  xLoc = xLoc + xVelocity;

  if ( (xLoc >= width) || (xLoc <= 0) ) {
    //println(xVelocity);
    xVelocity = xVelocity * -1;
    rad = rad + radVel;
    if (rad > 25) {
      radVel = radVel * -1;
    }
  }

}