📝 improve visual effect of test/langtons-ant

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";
     }