PosMover pm;
SpeedMover sm;

void setup(){
 size(250,250); 
 sm = new SpeedMover();
pm = new PosMover();
 mouseX = width/2;
 mouseY = height/2;


}
void draw(){
   background(200);
   sm.move();
  sm.draw(); 
	pm.move();
	pm.draw();
}

abstract class Mover{
   float x,y,xs,ys;
   float sz;


   Mover(){
      x = width / 2;
     y = height / 2;
    sz = width / 40; 
   }
   

abstract void move();

  void draw(){
     ellipse(x,y,sz*2,sz*2); 
  }
  
  
}
class SpeedMover extends Mover{
   float ACCEL = .1;
  void move(){
    if(keyPressed){
      if(keyCode == UP) ys -= ACCEL;
      if(keyCode == DOWN) ys += ACCEL;
      if(keyCode == LEFT) xs -= ACCEL;
      if(keyCode == RIGHT) xs += ACCEL;    
    }
    x += xs;
    y += ys;
    
    if(x < 0 || x > width) {
        xs *= -.5;
        x += xs;
    }
    if(y < 0 || y > width) {
        ys *= -.5;
        y += ys;
    }
    
  } 


}

class PosMover extends Mover{
float MOVE = 2;
 void move(){
    if(keyPressed){
      if(keyCode == UP) y -= MOVE;
      if(keyCode == DOWN) y += MOVE;
      if(keyCode == LEFT) x -= MOVE;
      if(keyCode == RIGHT) x += MOVE;
    }
}
}