--------W.java
import java.awt.*;import java.awt.event.*;import java.awt.image.*;public class
W extends java.applet.Applet{ImageProducer s;int w=64,T=4;int[] p=new int[w*w]
,v=new int[w*w];byte[] q=new byte[w*w],r=new byte[256],b=new byte[256];public
void update(Graphics g){g.drawImage(createImage(s),0,0,w*T,w*T,0,0,w,w,null);}
public boolean mouseDown(Event e,int x,int y){v[x/T+y/T*w]+=128;return true;}{
byte d=(byte)-128;for(int i=0;i<256;i++){r[(d++)&255]=(byte)i;b[i]=(byte)255;}
s=new MemoryImageSource(w,w,new IndexColorModel(8,256,r,r,b),q,0,w);new Thread
(){public void run(){for(;;){for(int i=w+1;i<w*w-w;i++){v[i]+=(p[i-w]+p[i-1]+p
[i+1]+p[i+w])/4-p[i];p[i-w]+=v[i-w];q[i]=(byte)(p[i-w-1]-p[i]);}repaint();try{
sleep(50);}catch(Exception e){return;}}}}.start();}}

--------w.html
<HTML><BODY>
<APPLET CODEBASE="." CODE="W.class" WIDTH="255" HEIGHT="255"></APPLET>
</BODY></HTML>

--------README
なんか汚い
パレット生成部分に無駄があるっぽい
挙動がやばい
ツッコミは勘弁