int num = 25;
myLine[] lines = new myLine[num];
color bg = #000000;
color f = #00CCCC;
color s = #006666;
float y, theta, diam;
float speed = .4;

void setup() {
  size(500, 500);
  background(bg);

  for (int i=0; i<lines.length; i++) {
    float _y = i*(height/num);
    lines[i]= new myLine(_y);
  }
}

void draw() {
  background(bg);
  fill(f);
  stroke(s);
  strokeWeight(3);
  ellipse(width/2, height/2, 300, 300);

  for (int i=0; i<lines.length; i++) {
    lines[i].display();
  }
  fill(bg);
  stroke(f);
  strokeWeight(20);
  diam = map(sin(theta), -1, 1, 100, 200);
  ellipse(width/2, height/2, diam, diam);
  theta += .03;

}
class myLine {
  float y;

  myLine(float _y) {
    y = _y;
  }

  void display() {
    strokeWeight(10);
    stroke(bg);
    y -= speed;
    if (y < 0) y = height;
    line(0, y, width, y);
  }
}