JS1k: The JavaScript code golfing competition

var M=Math,R=M.random,F=M.floor,W=250,WW=W*W,WW1=W*(W-1),W4=W*4;D=document;B=D.body;C=B.children[0];C.width=W;C.height=W;c=C.getContext("2d");c.fillRect(0,0,W,W);d=c.getImageData(0,0,W,W);p=d.data;r=40;r2=2*r;w2r=W-2*r2;for(i=0;i<10;i++){x0=r2+R()*w2r;y0=r2+R()*w2r;for(j=0;j<8000;j++){x=r-R()*r2;y=r-R()*r2;l=(x*x+y*y)/32;p[(F(x0+x/l)+F(y0+y/l)*W)*4]=R()*255;}}c.putImageData(d,0,0);function _(){for(i=1;i<WW1;i++){j=i*4;z=p[j-W4-4]+p[j-W4]+p[j-W4+4]+p[j-4]+p[j]*8+p[j+4]+p[j+W4-4]+p[j+W4]+p[j+W4+4];z/=16;if(z>195){p[j+W4]+=p[j]*0.2;}p[j]--;}c.putImageData(d,0,0);}setInterval("_()",10);

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