// Delete ImageJ/plugins/jars/BeanShell.jar and restart ImageJ if
// this script takes more than a few seconds to run. ImageJ will
// download a faster version the next time you run a BeanShell script.

     t0 = System.currentTimeMillis();
     size = 512;
     ip = new FloatProcessor(size,size);
     for (int y=0; y<size; y++) {
        IJ.showProgress(y,size-1);
        for (x=0; x<size; x++) {
           dx=x-size/2; dy=y-size/2;
           d = Math.sqrt(dx*dx+dy*dy);
           ip.setf(x,y,(float)-d);
        }
    }
    time = (System.currentTimeMillis()-t0)/1000.0+" seconds";
    img = new ImagePlus(""+time,ip);
    IJ.run(img,"Red/Green","");
    img.show();