JS1k: The JavaScript code golfing competition

// some cute animal emojis - enjoy :)
A=50,B=A*2,O=A*5,P=O*2,C=[];c.font='80px serif';for(D=0;D<39;D++){c.clearRect(0,0,P,P);c.fillText(String.fromCodePoint(0x1F400+D),A,75);C[D]=new Image();C[D].src=a.toDataURL()};q=0;r=requestAnimationFrame;n=Date.now;h=Math;l=h.random;f=[];c.lineWidth=A*1.5;N=h.PI*2;M=function(i,a,s,d,b){this.i=i;this.d=d;b=h.round(l()*38);this.a=(p,r)=>{p=(n()-s)/d;r=O*p;c.save();c.translate(r*h.cos(a),r*h.sin(a));c.scale(p*2,p*2);c.rotate(a+h.PI/2);c.drawImage(C[b],-A,-A,P,P);c.restore();return p<1}};j=(i)=>{f.splice(i,1,new M(i,(i/100)*N,n(),P*6-l()*P*4))};for(i=0;i<100;){j(i++)}a.style.background='#fff';W=n();V=X=Y=Z=0;(e=()=>{X=n();Z=W+3e3;if(X>Z){W=X;Y=!V;V=Y;}else if(X>Z-O&&X<Z){Y=!Y;}a.style.filter=Y?'invert()':'';c.clearRect(0,0,P,P);c.save();c.translate(O,O);c.rotate(q+=.01);for(g of f){g.a()||j(g.i);};c.globalCompositeOperation='destination-in';c.beginPath();R=0,S=q*-22;for(T=0;T<O;){R+=T++/B;S+=N/A;c.lineTo(R*h.cos(S),R*h.sin(S));}c.stroke();c.closePath();c.restore();r(e);})()

Ly8gc29tZSBjdXRlIGFuaW1hbCBlbW9qaXMgLSBlbmpveSA6KQ0KQT01MCxCPUEqMixPPUEqNSxQPU8qMixDPVtdO2MuZm9udD0nODBweCBzZXJpZic7Zm9yKEQ9MDtEPDM5O0QrKyl7Yy5jbGVhclJlY3QoMCwwLFAsUCk7Yy5maWxsVGV4dChTdHJpbmcuZnJvbUNvZGVQb2ludCgweDFGNDAwK0QpLEEsNzUpO0NbRF09bmV3IEltYWdlKCk7Q1tEXS5zcmM9YS50b0RhdGFVUkwoKX07cT0wO3I9cmVxdWVzdEFuaW1hdGlvbkZyYW1lO249RGF0ZS5ub3c7aD1NYXRoO2w9aC5yYW5kb207Zj1bXTtjLmxpbmVXaWR0aD1BKjEuNTtOPWguUEkqMjtNPWZ1bmN0aW9uKGksYSxzLGQsYil7dGhpcy5pPWk7dGhpcy5kPWQ7Yj1oLnJvdW5kKGwoKSozOCk7dGhpcy5hPShwLHIpPT57cD0obigpLXMpL2Q7cj1PKnA7Yy5zYXZlKCk7Yy50cmFuc2xhdGUocipoLmNvcyhhKSxyKmguc2luKGEpKTtjLnNjYWxlKHAqMixwKjIpO2Mucm90YXRlKGEraC5QSS8yKTtjLmRyYXdJbWFnZShDW2JdLC1BLC1BLFAsUCk7Yy5yZXN0b3JlKCk7cmV0dXJuIHA8MX19O2o9KGkpPT57Zi5zcGxpY2UoaSwxLG5ldyBNKGksKGkvMTAwKSpOLG4oKSxQKjYtbCgpKlAqNCkpfTtmb3IoaT0wO2k8MTAwOyl7aihpKyspfWEuc3R5bGUuYmFja2dyb3VuZD0nI2ZmZic7Vz1uKCk7Vj1YPVk9Wj0wOyhlPSgpPT57WD1uKCk7Wj1XKzNlMztpZihYPlope1c9WDtZPSFWO1Y9WTt9ZWxzZSBpZihYPlotTyYmWDxaKXtZPSFZO31hLnN0eWxlLmZpbHRlcj1ZPydpbnZlcnQoKSc6Jyc7Yy5jbGVhclJlY3QoMCwwLFAsUCk7Yy5zYXZlKCk7Yy50cmFuc2xhdGUoTyxPKTtjLnJvdGF0ZShxKz0uMDEpO2ZvcihnIG9mIGYpe2cuYSgpfHxqKGcuaSk7fTtjLmdsb2JhbENvbXBvc2l0ZU9wZXJhdGlvbj0nZGVzdGluYXRpb24taW4nO2MuYmVnaW5QYXRoKCk7Uj0wLFM9cSotMjI7Zm9yKFQ9MDtUPE87KXtSKz1UKysvQjtTKz1OL0E7Yy5saW5lVG8oUipoLmNvcyhTKSxSKmguc2luKFMpKTt9Yy5zdHJva2UoKTtjLmNsb3NlUGF0aCgpO2MucmVzdG9yZSgpO3IoZSk7fSkoKQ==

//sorry, i don't really have a coherent source for this, did it really quick and dirty