JS1k: The JavaScript code golfing competition

/*possan.se*2010*/M=Math;MS=M.sin;MC=M.cos;MQ=M.sqrt;MP=M.PI;MP2=MP*2;d=document;
d.body.style.backgroundColor="#222";c=d.getElementById('c');G=c.getContext('2d');
W=240;H=160;c.width=W;c.height=H;HW=W/2;HH=H/2;A0=A1=A2=A3=0;ox=oy=oz=0;
tu=tv=0;rotate=function(t){cc=MC(t);ss=MS(t);z=X*cc-Y*ss;Y=X*ss+Y*cc;X=z;
};setInterval(function(){b=G.getImageData(0,0,W,H);d=b.data;o=0;for(y=0;
y<H;y++)for(x=0;x<W;x++){dx=(x-HW)/W;dy=(y-HH)/H;dz=-1;l=MQ(dx*dx+dy*dy+dz*dz);
dx/=l;dy/=l;dz/=l;X=dx;Y=dy;rotate(A0-A2);dy=Y;Y=dz;dx=X;X=dy;rotate(A3);
dy=X;dz=Y;R=100;A=dx*dx+dy*dy;B=2*(dx*ox+dy*oy);C=ox*ox+oy*oy-R*R;rd=MQ(B*B-4*A*C);
q=-.5*(B-rd);t1=C/q;tu=M.atan2(dy,dx)/MP2;tv=dz*t1/256;tv+=A1;tu*=5;g=(tu*256)^(tv*256);
g&=255;d[o++]=g;d[o++]=g;d[o++]=g;d[o++]=255;};G.putImageData(b,0,0);A0+=0.015;
A1+=0.026;A2+=0.041;A3+=0.009;},10);

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