JS1k: The JavaScript code golfing competition

M=[];l=N=800;e=f=h=i=j=0;with(document.body){B=children[0];B.height=l;B.width=l;onmousemove=function(p){e=p.clientX;f=p.clientY};onmousedown=function(){j=1};onmouseup=function(){j=0};X=B.getContext("2d")}with(k=Math){r=random;S=sin;C=cos;A=abs;while(N--)M[N]={q:"rgb(40,40,"+min(255,40+floor(r()*255))+")",x:l*.5,y:l*.5,z:C(N)*r()*25,w:S(N)*r()*2,s:2}}setInterval("X.globalCompositeOperation='source-over';X.fillStyle='#000';X.fillRect(0,0,l,l);X.globalCompositeOperation='lighter';a=e-h;b=f-i;h=e;i=f;for(H=l/1.5,c=l/8,K=l/2,P=l;P--;){L=M[P];Q=L.x;R=L.y;I=L.z;J=L.w;O=Q-e;G=R-f;F=k.sqrt(O*O+G*G);G=k.atan2(G,O);O=C(G);G=S(G);if(j)if(F<K){E=(1-F/K)*15;I+=O*E+.5-r();J+=G*E+.5-r()}if(F<c){F=(1-F/c)*l*.00012;I+=a*F;J+=b*F}I*=.95;J*=.95;F=A(I);O=A(J);G=(F+O)*1.5;I*=F<.1?r()*3:1;J*=O<.1?r()*3:1;F=G*.5;F=k.max(k.min(F,3.5),.4);Q+=I;R+=J;if(Q>l){Q=l;I*=-1}else{if(Q<0){Q=0;I*=-1}}if(R>l){R=l;J*=-1}else{if(R<0){R=0;J*=-1}}L.z=I;L.w=J;L.x=Q;L.y=R;X.fillStyle=L.q;X.beginPath();X.arc(Q,R,F,0,13,1);X.fill()}",33);

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