JS1k: The JavaScript code golfing competition

var k=document.body,f=k.children[0],e=f.getContext("2d"),c=[],b=256,h,i,a,d=Math,g=d.random;k.style.cssText="margin:0;text-align:center;background-color:#000";f.width=800;for(f.height=600;b--;)c.push([800*g(),600*g(),g()-0.5]);setInterval(function(){e.drawImage(f,-4,-4,808,608);for(b=256;b--;){a=a>-5?c[b][2]:0;a+=g()-0.5;var j=c[b][0]+d.cos(a)*a;h=d.min(d.max(j,0),800);j=c[b][1]+d.sin(a)*a;i=d.min(d.max(j,0),600);e.beginPath();e.fillStyle=a>0?a>0.25?"rgba(0,0,0,0.03)":"rgba(0,0,255,0.03)":a<-0.75?"rgba(0,255,255,0.01)":"rgba(255,0,0,0.02)";e.rect(h,i,128,256);e.fill();c[b][0]=h;c[b][1]=i;c[b][2]=a}},9)

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