Simple pseudo3D twister effect in vertical bar with 2 colours

Twister_bicolour.pde

//https://www.dwitter.net/d/20135
//https://democyclopedia.wordpress.com/2015/11/29/t-comme-twister/
//more info:
//http://eab.abime.net/showthread.php?t=59865&page=5
float b, d, n, m, r, t;
void setup() {
  size(1280, 720);
  noStroke();
}
void draw() {
  clear();
  t+=.01;
  t%=92.2;
  for (float y=height; y>0; y-=2) {
    d=twister(r=y/255,r);
    //d=cos(r)-sin(r); //simple Twist
    for (float i=4; i>0; i--) {
      //uniform rotation
      //n=twister(i, r);
      //m=twister(i+1, r);
      
      //more wild rotations
      n=twister(i, r*cos(t*constrain(tan(t*.1),-PI/4,PI/4)));
      m=twister(i+1, r*cos(t*constrain(tan(t*.1),-PI/4,PI/4)));
      
      b=255*(m-n)/70;
      fill(i%2==0?0:b/2, 255-i%2==0?0:b/3, i%2==0?b:0);
      if (n<m) rect(n+d+width/2, y, m-n, 2);
    }
  }
}
float twister(float I, float r) {
  return sin(t*3+r+I*1.57)*60;
}