Kugel[] kugeln = new Kugel[20];

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

  background(255);
  stroke(0,10);
  strokeWeight(0);
  noFill();

  for(int i = 0; i < kugeln.length;i= i+1){
    kugeln[i] = new Kugel(20,color(255,0,0));
  }
}

void draw(){
  beginShape();

  for(int i = 0; i < kugeln.length;i= i+1){
    vertex(kugeln[i].myPosX,kugeln[i].myPosY);
    //kugeln[i].draw();
    kugeln[i].update();
  }
  endShape(CLOSE);
}

class Kugel{
  float mySpeedX;
  float mySpeedY;

  float myBowlSize;
  float myHalfBowlSize;

  float myPosX;
  float myPosY;

  color myColor;

  Kugel(float theBowlSize, color theColor){
    myBowlSize = theBowlSize;
    myHalfBowlSize = myBowlSize/2;

    mySpeedX = random(5);
    mySpeedY = random(5);

    myPosX = myHalfBowlSize;
    myPosY = myHalfBowlSize;

    posAltX = myPosX;
    posAltY = myPosY;

    myColor = theColor;
  }

  float posAltX;
  float posAltY;



  void update(){
    if(myPosX > width - myHalfBowlSize){
      mySpeedX = -mySpeedX;
    }
    if(myPosY > height - myHalfBowlSize){
      mySpeedY = -mySpeedY;
    }
    if(myPosX < myHalfBowlSize){
      mySpeedX = -mySpeedX;
    }
    if(myPosY < myHalfBowlSize){
      mySpeedY = -mySpeedY;
    }

    posAltX = myPosX;
    posAltY = myPosY;

    myPosX = myPosX + mySpeedX;
    myPosY = myPosY + mySpeedY;
  }

  void draw(){
    fill(myColor);
    line(myPosX,myPosY,posAltX,posAltY);

  }
}