diff --git a/README.md b/README.md
index 87ef968..82ac078 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # __Nasal - Modern Interpreter__
 
-<img src="./doc/pic/header.png" style="width:800px"></img>
+<img src="./doc/pic/header.png" style="width:600px"></img>
 
 ![GitHub code size](https://img.shields.io/github/languages/code-size/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
 ![GitHub release(latest by date)](https://img.shields.io/github/v/release/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
diff --git a/doc/README_zh.md b/doc/README_zh.md
index 8803905..ddb213f 100644
--- a/doc/README_zh.md
+++ b/doc/README_zh.md
@@ -1,6 +1,6 @@
 # __Nasal - Modern Interpreter__
 
-<img src="../doc/pic/header.png" style="width:800px"></img>
+<img src="../doc/pic/header.png" style="width:600px"></img>
 
 ![GitHub code size](https://img.shields.io/github/languages/code-size/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
 ![GitHub release(latest by date)](https://img.shields.io/github/v/release/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
diff --git a/src/main.cpp b/src/main.cpp
index 9002f7c..0955be9 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -58,9 +58,10 @@ std::ostream& help(std::ostream& out) {
     << "   -f,   --ref-file | get referenced files.\n"
     << "   -dbg, --debug    | debug mode.\n"
     << "         --prof     | show profiling result, available in debug mode.\n"
-    << "         --prof-all | show profiling result of all files,"
+    << "         --prof-all | show profiling result of all files, "
     << "available under debug mode.\n"
-    << "         --limit    | use limited execution mode."
+    << "         --limit    | use limited execution mode "
+    << "(readonly api enabled).\n"
     << "file:\n"
     << "   <filename>       | execute file.\n"
     << "argv:\n"
@@ -116,10 +117,9 @@ void err() {
     std::exit(1);
 }
 
-void execute(
-    const std::string& file,
-    const std::vector<std::string>& argv,
-    const u32 cmd) {
+void execute(const std::string& file,
+             const std::vector<std::string>& argv,
+             const u32 cmd) {
 
     using clk = std::chrono::high_resolution_clock;
     const auto den = clk::duration::period::den;
diff --git a/test/langtons-ant.nas b/test/langtons-ant.nas
index 9eed9a9..adb5322 100644
--- a/test/langtons-ant.nas
+++ b/test/langtons-ant.nas
@@ -37,11 +37,12 @@ foreach(var a; ants) {
 }
 
 var print_map = func {
+    var pics = ["  ", "[]"];
     var res = "\e[1;1H";
     for(var y = 0; y<30; y += 1) {
         for(var x = 0; x<60; x += 1) {
             res ~= "\e[38;5;"~map_color[x + y*60]~";1m";
-            res ~= map[x + y*60] ~ " \e[0m";
+            res ~= pics[map[x + y*60]] ~ "\e[0m";
         }
         res ~= "\n";
     }