diff --git a/balloon/example/bp.nas b/balloon/example/bp.nas
new file mode 100644
index 0000000..47e9d0b
--- /dev/null
+++ b/balloon/example/bp.nas
@@ -0,0 +1,131 @@
+
+var neuron=
+{
+    in:0,
+    out:0,
+    diff:0,
+    bia:0,
+    w:[]
+};
+
+var INUM=2;
+var HNUM=4;
+var ONUM=1;
+
+var input_layer=[];
+var hidden=[];
+var output=[];
+var expect=[];
+
+var difftanh=func(x)
+{
+    var ret=tanh(x);
+    return 1-ret*ret;
+};
+
+var diffsigmoid=func(x)
+{
+    var ret=sigmoid(x);
+    return ret*(1-ret);
+};
+
+var init=func()
+{
+    for(var i=0;i<INUM;i+=1){append(input_layer,0);}
+    for(var i=0;i<HNUM;i+=1)
+    {
+        append(hidden,neuron);
+        for(var j=0;j<INUM;j+=1){append(hidden[i].w,rand());}
+        hidden[i].bia=rand();
+    }
+    for(var i=0;i<ONUM;i+=1)
+    {
+        append(expect,0);
+        append(output,neuron);
+        for(var j=0;j<HNUM;j+=1){append(output[i].w,rand());}
+        output[i].bia=rand();
+    }
+    return;
+};
+
+var calc=func()
+{
+    for(var i=0;i<HNUM;i+=1)
+    {
+        hidden[i].in=hidden[i].bia;
+        for(var j=0;j<INUM;j+=1){hidden[i].in+=input_layer[j]*hidden[i].w[j];}
+        hidden[i].out=tanh(hidden[i].in);
+    }
+    for(var i=0;i<ONUM;i+=1)
+    {
+        output[i].in=output[i].bia;
+        for(var j=0;j<HNUM;j+=1){output[i].in+=hidden[j].out*output[i].w[j];}
+        output[i].out=sigmoid(output[i].in);
+    }
+    var error=0;
+    for(var i=0;i<ONUM;i+=1){error+=(expect[i]-output[i].out)*(expect[i]-output[i].out);}
+    error*=0.5;
+    return error;
+};
+
+var back=func()
+{
+    var lr=0.9;
+    for(var i=0;i<ONUM;i+=1){output[i].diff=(expect[i]-output[i].out)*diffsigmoid(output[i].in);}
+    for(var i=0;i<HNUM;i+=1)
+    {
+        hidden[i].diff=0;
+        for(var j=0;j<ONUM;j+=1){hidden[i].diff+=output[j].diff*output[j].w[i];}
+        hidden[i].diff*=difftanh(hidden[i].in);
+    }
+    for(var i=0;i<HNUM;i+=1)
+    {
+        hidden[i].bia+=lr*hidden[i].diff;
+        for(var j=0;j<INUM;j+=1){hidden[i].w[j]+=lr*input_layer[j]*hidden[i].diff;}
+    }
+    for(var i=0;i<ONUM;i+=1)
+    {
+        output[i].bia+=lr*output[i].diff;
+        for(var j=0;j<HNUM;j+=1){output[i].w[j]+=lr*hidden[j].out*output[i].diff;}
+    }
+    return;
+};
+
+init();
+var cnt=0;
+var total_error=10;
+while(total_error>0.001)
+{
+    total_error=0;
+    input_layer[0]=1;input_layer[1]=1;expect[0]=1;
+    total_error+=calc();
+    back();
+    input_layer[0]=1;input_layer[1]=0;expect[0]=1;
+    total_error+=calc();
+    back();
+    input_layer[0]=0;input_layer[1]=1;expect[0]=1;
+    total_error+=calc();
+    back();
+    input_layer[0]=0;input_layer[1]=0;expect[0]=0;
+    total_error+=calc();
+    back();
+    cnt+=1;
+    if(cnt==10)
+    {
+        print('10 times: ',total_error,'\n');
+        cnt=0;
+    }
+}
+
+input_layer[0]=1;input_layer[1]=1;expect[0]=1;
+calc();
+print('1 or 1: ',output[0].out,'\n');
+input_layer[0]=1;input_layer[1]=0;expect[0]=1;
+calc();
+print('1 or 0: ',output[0].out,'\n');
+input_layer[0]=0;input_layer[1]=1;expect[0]=1;
+calc();
+print('0 or 1: ',output[0].out,'\n');
+input_layer[0]=0;input_layer[1]=0;expect[0]=0;
+calc();
+print('0 or 0: ',output[0].out,'\n');
\ No newline at end of file
diff --git a/balloon/example/brainfuck.nas b/balloon/example/brainfuck.nas
new file mode 100644
index 0000000..eefba3c
--- /dev/null
+++ b/balloon/example/brainfuck.nas
@@ -0,0 +1,71 @@
+
+var resource=[];
+var data=[];
+var ptr=0;
+for(var i=0;i<1024;i+=1){append(data,0);}
+
+var input_file=func(str)
+{
+    resource=[];
+    var res=read(str);
+    for(var i=0;i<size(res);i+=1)
+    {
+        var ch=chars(res[i]);
+        for(var j=0;j<size(ch);j+=1){append(resource,ch[j]);}
+    }
+    return;
+};
+var runloop=func(times,begin)
+{
+    var ends=begin;
+    for(var t=0;t<times;t+=1)
+    {
+        for(var i=begin;i<size(resource);i+=1)
+        {
+            if(resource[i]=='+'){data[ptr]+=1;}
+            else if(resource[i]=='-'){data[ptr]-=1;}
+            else if(resource[i]=='>'){ptr+=1;}
+            else if(resource[i]=='<'){ptr-=1;}
+            else if(resource[i]=='.'){print(data[ptr],' ');}
+            else if(resource[i]==','){data[ptr]=num(input());}
+            else if(resource[i]=='[')
+            {
+                var t_ends=runloop(data[ptr],i+1);
+                i=t_ends;
+            }
+            else if(resource[i]==']'){ends=i;break;}
+            else{print('error token: ',resource[i],'\n');}
+        }
+    }
+    return ends;
+};
+var runtime=func()
+{
+    for(var i=0;i<1024;i+=1){data[i]=0;}
+    ptr=0;
+    for(var i=0;i<size(resource);i+=1)
+    {
+        if(resource[i]=='+'){data[ptr]+=1;}
+        else if(resource[i]=='-'){data[ptr]-=1;}
+        else if(resource[i]=='>'){ptr+=1;}
+        else if(resource[i]=='<'){ptr-=1;}
+        else if(resource[i]=='.'){print(data[ptr],' ');}
+        else if(resource[i]==','){data[ptr]=num(input());}
+        else if(resource[i]=='[')
+        {
+            var ends=runloop(data[ptr],i+1);
+            i=ends;
+        }
+        else{print('error token: ',resource[i],'\n');}
+    }
+    return;
+};
+while(1)
+{
+    print("bf> ");
+    var filename=input();
+    if(filename=='exit'){break;}
+    input_file(filename);
+    runtime();
+    print('\n');
+}