diff --git a/nasal_builtin.h b/nasal_builtin.h
index 8ddb933..5f4350c 100644
--- a/nasal_builtin.h
+++ b/nasal_builtin.h
@@ -526,7 +526,7 @@ var builtin_chr(var* local,gc& ngc) {
 }
 
 var builtin_char(var* local,gc& ngc) {
-    return ngc.newstr((char)local[1].num());
+    return ngc.newstr((unsigned char)local[1].num());
 }
 
 var builtin_values(var* local,gc& ngc) {
diff --git a/test/life.nas b/test/life.nas
index 865d857..d5d7c1d 100644
--- a/test/life.nas
+++ b/test/life.nas
@@ -1,23 +1,17 @@
-var map=nil;
+import.stl.process_bar;
 
-var check=func(x,y){
-    if(x>29) x=0;
-    if(y>49) y=0;
-    return map[x][y];
-}
-
-var new_map=func(){
+var new_map=func(width,height){
     var tmp=[];
-    setsize(tmp,30);
+    setsize(tmp,height);
     forindex(var i;tmp){
         tmp[i]=[];
-        setsize(tmp[i],50);
+        setsize(tmp[i],width);
     }
     return tmp;
 }
 
-var prt=func(){
-    var s='\e[0;0H';
+var prt=func(map){
+    var s='\e[1;1H';
     foreach(var line;map){
         foreach(var elem;line)
             s~=elem~' ';
@@ -27,32 +21,135 @@ var prt=func(){
     unix.sleep(1/160);
 }
 
-func(){
+var run=func(width,height){
+
+    var check=func(_width,_height){
+        if(_height>=height) _height=0;
+        if(_width>=width) _width=0;
+        return map[_height][_width]=='O';
+    }
     # enable ANSI escape sequence
     if(os.platform()=="windows")
         system("color");
     print("\ec");
     rand(time(0));
-    map=new_map();
+    var map=new_map(width,height);
+    var tmp=new_map(width,height);
 
     forindex(var i;map)
         forindex(var j;map[i])
-            map[i][j]=rand()<0.45?'O':' ';
+            map[i][j]=rand()<0.45?'O':'.';
 
-    var calc=[[0,1],[1,0],[0,-1],[-1,0],[1,1],[1,-1],[-1,-1],[-1,1]];
     for(var r=0;r<400;r+=1){
         prt(map);
-        var tmp=new_map();
-        for(var i=0;i<30;i+=1)
-            for(var j=0;j<50;j+=1){
-                var cnt=0;
-                foreach(var k;calc)
-                    cnt+=(check(i+k[0],j+k[1])=='O');
+        for(var i=0;i<height;i+=1)
+            for(var j=0;j<width;j+=1){
+                var cnt=check(j,i+1)+check(j+1,i)+check(j,i-1)+check(j-1,i)+check(j+1,i+1)+check(j-1,i-1)+check(j+1,i-1)+check(j-1,i+1);
                 if(cnt==2)    tmp[i][j]=map[i][j];
                 elsif(cnt==3) tmp[i][j]='O';
-                else          tmp[i][j]=' ';
+                else          tmp[i][j]='.';
             }
-        map=tmp;
+        (map,tmp)=(tmp,map);
     }
     return;
-}();
\ No newline at end of file
+};
+
+var ppm_gen=func(width,height){
+
+    # iteration counter and trigger for ppm/data generator
+    var iter_to_print=0;
+
+    var init=func(){
+        var res=new_map(width,height);
+        if(io.exists(".life_data")) {
+            var vec=split("\n",io.fin(".life_data"));
+            if (num(vec[0])!=width or num(vec[1])!=height) {
+                die("incorrect width or height: "~vec[0]~":"~str(width)~" / "~vec[1]~":"~str(height))
+            }
+            iter_to_print=num(vec[2]);
+            var data=split("",vec[3]);
+            for(var i=0;i<height;i+=1)
+                for(var j=0;j<width;j+=1)
+                    res[i][j]=num(data[i*width+j]);
+            return res;
+        }
+
+        rand(time(0));
+        for(var i=0;i<height;i+=1)
+            for(var j=0;j<width;j+=1)
+                res[i][j]=0;
+        
+        for(var i=int(height/5*2);i<int(height/5*3);i+=1)
+            forindex(var j;res[i])
+                res[i][j]=rand()<0.5?1:0;
+        return res;
+    }
+
+    var store=func(){
+        var fd=io.open(".life_data","w");
+        io.write(fd,str(width)~"\n"~str(height)~"\n"~str(iter_to_print)~"\n");
+        for(var i=0;i<height;i+=1){
+            for(var j=0;j<width;j+=1){
+                io.write(fd,map[i][j]==1?"1":"0");
+            }
+        }
+        io.close(fd);
+    }
+
+    var gen=func(filename){
+        # P3 use ASCII number
+        # P6 use binary character
+        var fd=io.open(filename,"wb");
+        io.write(fd,"P6\n"~width~" "~height~"\n255\n");
+        var white=char(255)~char(255)~char(255);
+        var black=char(0)~char(0)~char(0);
+        for(var i=0;i<height;i+=1){
+            for(var j=0;j<width;j+=1){
+                var s=map[i][j]==1?white:black;
+                io.write(fd,s);
+            }
+        }
+        io.close(fd);
+    }
+
+    var ts=maketimestamp();
+    var bar=process_bar.high_resolution_bar(80);
+    var map=init();
+    var tmp=new_map(width,height);
+    
+    var check=func(_width,_height){
+        if(_height>=height) _height=0;
+        if(_width>=width) _width=0;
+        return map[_height][_width]==1;
+    }
+
+    for(var r=0;r<1001;r+=1){
+        ts.stamp();
+        for(var i=0;i<height;i+=1){
+            for(var j=0;j<width;j+=1){
+                var cnt=check(j,i+1)+check(j+1,i)+check(j,i-1)+check(j-1,i)+check(j+1,i+1)+check(j-1,i-1)+check(j+1,i-1)+check(j-1,i+1);
+                if(cnt==2)    tmp[i][j]=map[i][j];
+                elsif(cnt==3) tmp[i][j]=1;
+                else          tmp[i][j]=0;
+            }
+        }
+        (map,tmp)=(tmp,map);
+        var calc_tm=ts.elapsedMSec();
+        var duration=int(calc_tm/1000*(1e3-r));
+        if(r-int(r/10)*10==0) {
+            if(r){
+                store();
+            }
+            gen("iteration_"~str(iter_to_print)~".ppm");
+            iter_to_print+=10;
+        }
+        print(bar.bar((r+1)/1e3),int((r+1)/1e3*100),"% ",calc_tm," ms, ",int(duration/60)," min ",duration-int(duration/60)*60," s remaining, iteration ",r,"   \r");
+    }
+    println();
+}
+
+if (size(runtime.argv()) and runtime.argv()[0]=="--generate-ppm") {
+    ppm_gen(1500*4,1500);
+} else {
+    run(80,30);
+}
\ No newline at end of file