squares

Square[] squares;
int elem, unit;
color f;

void setup() {
  size(500, 500);
  background(255);

  int counter=0;
  int i=0;
  int div = 4;
  unit = width/div;
  elem = int(sq(div));
  squares = new Square[elem];

  for (int x = unit/2; x<width; x +=unit) {
    counter = 0;
    for (int y = unit/2; y<height; y +=unit) {

      squares[i] = new Square(float(x), float(y), counter);
      i++;
      counter++;
    }
  }
}

void draw() {
  background(255);
  for (int i=0; i<elem; i++) {
    squares[i].display();
  }

    if (frameCount % 2 == 0 & frameCount<121) saveFrame("image-####.gif");

}
class Square {
  float x, y, theta,f;
  float x1, x2, x3, x4, y1, y2, y3, y4;
  float nx1, nx2, nx3, nx4, ny1, ny2, ny3, ny4;
  float sz = unit*.3;
  PVector pv;
  int c;

  Square(float _x, float _y, int _counter) {
    x = _x;
    y = _y;
    c = _counter;
    x1 = x-sz;
    y1 = y-sz;
    x2 = x;
    y2 = y-sz;
    x3 = x-sz;
    y3 = y;
    x4 = x;
    y4 = y;

    pv = new PVector(unit/2-sz, unit/2-sz);
  }

  void display() {

    nx1 = map(sin(theta), -1, 1, x1-pv.x, x1);
    ny1 = map(sin(theta), -1, 1, y1-pv.y, y1);
    nx2 = map(sin(theta), -1, 1, x2+pv.x,x2);
    ny2 = map(sin(theta), -1, 1, y2-pv.y,y2);
    nx3 = map(sin(theta), -1, 1, x3-pv.x, x3);
    ny3 = map(sin(theta), -1, 1, y3+pv.y, y3);
    nx4 = map(sin(theta), -1, 1, x4+pv.x, x4);
    ny4 = map(sin(theta), -1, 1, y4+pv.y, y4);
    f = map(sin(theta),-1,1,100,180);

    fill(f);
    stroke(f);
    strokeWeight(5);
    rect(nx1, ny1, sz, sz);
    rect(nx2, ny2, sz, sz);
    rect(nx3, ny3, sz, sz);
    rect(nx4, ny4, sz, sz);

    theta += 0.0523;
  }
}