JS1k: The JavaScript code golfing competition

w=600;h=400;function r(z,n){return Math.floor(Math.random()*n+z);}c=document.getElementById('c');c.width=w;c.height=h;d=c.getContext('2d');g=3;function B(a,b,c,d){this.x=a;this.y=b;this.w=c;this.dx=d;this.dy=0;}b=new Array();for(i=0;i<r(3,9);i++){u=new B(r(0,550),r(0,350),r(15,50),r(5,10));b.push(u);}function U(){d.fillStyle="#000";d.fillRect(0,0,w,h);for(i=0;i<b.length;i++){d.strokeStyle="#000";d.strokeRect(b[i].x,b[i].y,b[i].w,b[i].w);d.fillStyle="#fff";d.fillRect(b[i].x,b[i].y,b[i].w,b[i].w);b[i].dy+=g;b[i].x+=b[i].dx;b[i].y+=b[i].dy;if(b[i].y+b[i].w>h){b[i].dy=-(b[i].dy)+g;b[i].y=h-b[i].w;}if(b[i].x+b[i].w>w){b[i].dx=-b[i].dx;b[i].x=w-b[i].w;}if(b[i].x<0){b[i].dx=-b[i].dx;b[i].x=0;}if(Math.abs(b[i].dy)<g&&b[i].w+b[i].y>=h){b[i].dy=r(-30,-20)}}}setInterval("U()",50);

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