diff --git a/stl/file.nas b/stl/file.nas
index 850a8c4..ce952dc 100644
--- a/stl/file.nas
+++ b/stl/file.nas
@@ -36,3 +36,25 @@ var find_all_files=func(path){
     unix.closedir(dd);
     return res;
 }
+
+var recursive_find_files=func(path){
+    if(!io.exists(path))
+        return nil;
+    var dd=unix.opendir(path);
+    var res={
+        dir:path,
+        files:[]
+    };
+    while(var n=unix.readdir(dd)){
+        if(unix.isfile(path~"/"~n)){
+            append(res.files,n);
+        }elsif(unix.isdir(path~"/"~n) and n!="." and n!=".."){
+            var tmp=recursive_find_files(path~"/"~n);
+            if(tmp!=nil)
+                append(res.files,tmp);
+        }
+
+    }
+    unix.closedir(dd);
+    return res;
+}
\ No newline at end of file
diff --git a/test/bp.nas b/test/bp.nas
index db5df08..df2e965 100644
--- a/test/bp.nas
+++ b/test/bp.nas
@@ -26,7 +26,7 @@ var diffsigmoid=func(x){
     return x*(1-x);
 }
 
-var (inum,hnum,onum)=(2,4,1);
+var (inum,hnum,onum)=(2,5,1);
 var training_set=[[0,0],[0,1],[1,0],[1,1]];
 var expect=[0,1,1,0];
 
@@ -112,8 +112,14 @@ while(error>0.0005){
         backward(i);
     }
     cnt+=1;
+    if(cnt>=3e5)
+        break;
+}
+if(cnt>=3e5){
+    print("failed to train, ",cnt," epoch.\n");
+}else{
+    print('finished after ',cnt,' epoch.\n');
 }
-print('finished after ',cnt,' epoch.\n');
 foreach(var v;training_set){
     run(v);
     print(v,': ',output[0].out,'\n');
diff --git a/test/filesystem.nas b/test/filesystem.nas
index 69f9de4..82ad9c0 100644
--- a/test/filesystem.nas
+++ b/test/filesystem.nas
@@ -1,11 +1,7 @@
-var fd=io.open("test/filesystem.nas");
-while((var line=io.readln(fd))!=nil)
-    println(line);
-io.close(fd);
-println(io.stat("test/filesystem.nas"));
-
-var files=func(dir){
-    var dd=unix.opendir(dir);
+var files=func(path){
+    if(!io.exists(path))
+        return [];
+    var dd=unix.opendir(path);
     var res=[];
     while(var n=unix.readdir(dd))
         append(res,n);
@@ -22,17 +18,19 @@ var prt=func(s,path){
         foreach(var j;s)
             print("\e[34m",j,"\e[0m");
         if(unix.isdir(path~"/"~f)){
-            println("\e[34m",i==last?"└─":"├─","\e[0m\e[36m",f," >\e[0m");
-            append(s,i==last?"  ":"│ ");
+            println("\e[34m",i==last?" └─":" ├─","\e[0m\e[36m[",f,"]>\e[0m");
+            append(s,i==last?"   ":" │ ");
             prt(s,path~"/"~f);
             pop(s);
         }elsif(unix.isfile(path~"/"~f)){
-            println("\e[34m",i==last?"└─":"├─","\e[0m\e[32m",f,"\e[0m");
+            println("\e[34m",i==last?" └─":" ├─","\e[0m\e[32m",f,"\e[0m");
         }else{
-            println("\e[34m",i==last?"└─":"├─","\e[0m\e[91m",f,"\e[0m");
+            println("\e[34m",i==last?" └─":" ├─","\e[0m\e[91m",f,"\e[0m");
         }
     }
 }
 
-println("\e[36mNasal-Interpreter >\e[0m");
+if(os.platform()=="windows")
+    system("chcp 65001");
+println("\e[36m[",unix.getcwd(),"]>\e[0m");
 prt([""],".");
\ No newline at end of file