JS1k: The JavaScript code golfing competition

M=Math;E=M.abs;R=M.random;C=document.body.children[Q=0];C.width=W=innerWidth;C.height=H=innerHeight-6;X=C.getContext("2d");X.m=X.moveTo;X.l=X.lineTo;P=200;A=[d={x:W/2,y:H/2,r:30},a={x:0,y:0},b={x:0,y:0,p:0,q:0,r:20},c={x:0,y:0}];onmousemove=function(e){a.x=e.pageX;a.y=e.pageY};onclick=function(){Q=~Q};setInterval('with(b){m=x-c.x,n=y-c.y,m*m+n*n<900?c.x=R(c.y=R(d.r++)*H)*W:0;_=(Q?-P:P);p+=(a.x-x)/P+(d.x-x)/_;q+=(a.y-y)/P+(d.y-y)/_;p*=.98;q*=.98;x+=p;y+=q;x-r<0?p=E(p,x=r):x+r>W?p=-E(p,x=W-r):0;y-r<0?q=E(q,y=r):y+r>H?q=-E(q,y=H-r):0;with(X){fillStyle=Q?"#900":"#009",fillRect(0,0,W,H),lineWidth=3,strokeStyle=fillStyle="#FFF",m(a.x,a.y),l(x,y),stroke(l(d.x,d.y));for(i in A)with(z=A[i])beginPath(m(x,y)),fill(arc(x,y,z.r||10,0,M.PI*2,true))}}',30)

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