JS1k: The JavaScript code golfing competition

A=Math,H=100,p=[50,50],X=0,N=M=E=[],w=40,h=15,D=10
R=function(m){return~~(A.random()*m)}
o=function(p,x,y){return p[0]^x|p[1]^y?0:1}
onkeypress=function(e){e=e.charCode-H
if(e>3&e<9){q=p.slice()
q[0]+=(e^4?e^8?0:1:-1)
q[1]+=(e^7?e^6?0:1:-1)
p=M[q[1]][q[0]]?p:q
for(k=0;k<D;k++)if(o(E[k],p[0],p[1])){X+=k
do{E[k]=[R(H),R(H)]}while(M[E[k][1]][E[k][0]])}O()}}
for(i=0;i<H;i++){M[i]=[]
for(j=0;j<H;j++)M[i][j]=(R(H)<w)?1:0}
for(i=0;i<H;i++)M[i][0]=M[i][H-1]=M[0][i]=M[H-1][i]=1
for(k=0;k<D;k++){do{E[k]=[R(H),R(H)]}while(M[E[k][1]][E[k][0]])N=[]
for(i=0;i<H;i++){N[i]=[]
for(j=0;j<H;j++){s=0
for(n=-1;n<2;n++)for(m=-1;m<2;m++)s+=!M[i+n]?1:(mn=M[i+n][j+m])?1:mn!=!1
N[i][j]=i>>3^6|j>>3^6&&s>5|k<5&!s}}M=N}(O=function(){S='<pre style=width:240pt;height:170pt;background:#444;color:#eee>Exp: '+X
for(i=A.max(p[1]-~~(h/2),0);i<p[1]+~~(h/2);i++){S+='\n'
for(j=A.max(p[0]-~~(w/2),0);j<p[0]+~~(w/2);j++){e=' '
for(k=1;k<D;k++)if(o(E[k],j,i))e=k
S+=o(p,j,i)?'@':!M[i]?' ':M[i][j]?'#':e}}b.innerHTML=S})()

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