float left=200,top=200,right=550,bottom=350;
float ballX=left, ballY=top+10, ballDX=3, ballDY=2;
float horizon=100;
 

void setup() {
  size(600,600);
}

void draw() {
  scene();
  ball();
  text( ballX, 10,10 );
}

void scene() {
  background(155,200,155); ///background color
  table();
}


void table() { 
    ////draw rectangle box
  fill(155,155,255);
  stroke(0);
  strokeWeight(5);
  rectMode(CORNERS);
  rect(left,top,right,bottom);

}

void ball() {
  /// check for bounce then move, draw ball
   if (ballX<left || ballX>right) ballDX= -ballDX;
   if (ballY<top || ballY>bottom) ballDY= -ballDY;
  ballX += ballDX;
  ballY += ballDY;
  fill(255,0,0);
  ellipse(ballX,ballY,20,20 );

}