Rectangle wave

color bg = #ECD078;
color cs =#D95B43, cm = #C02942, cl=#542437 ;
float div_m, div_s, div_l;
myRect[] s_rects = {
};
myRect[] m_rects = {
};
myRect[] l_rects = {
};

void setup() {
  size(500, 400);
  background(bg);
  stroke(0);
  rectMode(CENTER);

  float sz;
  float theta = 0;
  div_s = 16;
  div_m = 11;
  div_l = 6;

  for (int i=1; i < div_s; i++) {
    sz = width/div_s;
    myRect s_rect = new myRect(float(i), sz, theta, cs);
    s_rects = (myRect[])append(s_rects, s_rect);
    theta += TAU/div_s;
  }
  for (int i=1; i < div_m; i++) {
    sz = width/div_m;
    myRect m_rect = new myRect(float(i), sz, theta, cm);
    m_rects = (myRect[])append(m_rects, m_rect);
    theta += TAU/div_m;
  }
  for (int i=1; i < div_l; i++) {
    sz = width/div_l;
    myRect l_rect = new myRect(float(i), sz, theta, cl);
    l_rects = (myRect[])append(l_rects, l_rect);
    theta += TAU/div_l;
  }
}

void draw() {
  background(bg);
  for (int i=0; i < l_rects.length; i++) {
    l_rects[i].display();
  }
  for (int i=0; i < m_rects.length; i++) {
    m_rects[i].display();
  }
  for (int i=0; i < s_rects.length; i++) {
    s_rects[i].display();
  }
 }

class myRect {
  float sz_x, sz_y, x, y;
  float i, theta;
  color col;

  myRect(float _i, float _sz, float _theta, color _col) {
    y = height/2;
    sz_x = _sz;
    i = _i;
    theta = _theta;
    col = _col;
  }

  void display() {
    fill(col);
    strokeWeight(2);
    stroke(#ffffff);
    x = i * sz_x;
    sz_y = map(sin(theta), -1, 1, sz_x, sz_x*1.7);
    rect(x, y, sz_x, sz_y);
    theta -= 0.07;
  }
}