int XSIZE = 600; int YSIZE = 600;

void setup() {
   size(XSIZE,YSIZE);
   background(0);

   CreateImage();       }

void CreateImage() {
float xblocks = 1; 
float yblocks = 1;
float xfreq = 100;
float yfreq = 100;
   for (int y=1;y<YSIZE;y++) {
     for (int x=1;x<XSIZE;x++) {

      float i = PI*x*xblocks/XSIZE;
      float j = PI*y*yblocks/YSIZE;
      float k = PI*x*xfreq/XSIZE;
      float l = PI*y*yfreq/YSIZE;
               float a = tan(j) * sin(j) * sin(i)
*tan(i)/( sin(x/2) * sin(y/2) );

      float colorR = a / 17;
      float colorG = a * 3;
      float colorB = a * 2;

color c = color(colorR, colorG, colorB);
          float aa =
(tan(k*l/x+y))*(cos(k*l/x+y))+100;
      float colorR2 = aa * 10 ;
      float colorG2 = aa;
      float colorB2 = aa *120;
                color cc = color((colorR+colorR2)/2,
(colorG+colorG2)/2, 
(colorB+colorB2)/2);
       set(x,y,c);
     }
   }
   //saveFrame("_"+minute()+second()+".tif");
}