diff --git a/scripts/constants.js b/scripts/constants.js
index b7fa384..e2d4d86 100644
--- a/scripts/constants.js
+++ b/scripts/constants.js
@@ -34,7 +34,7 @@ ${locale.maroon} = (128, 50, 50);
 ${locale.purple} = (150, 100, 220);
 
 # Global variables.
-${locale.interval} = ${DEFAULT_INTERVAL}
+# ${locale.interval} = ${DEFAULT_INTERVAL}
 
 # Grid functions.
 def ${locale.size}(n, m):
@@ -43,6 +43,7 @@ def ${locale.size}(n, m):
 def ${locale.font}(size):
     grid.font(f"{size}pt")
 
+
 def ${locale.color}(i, j, col):
     if callable(col): col = col()
     grid.bgcolor(i, j, *col)
@@ -50,12 +51,14 @@ def ${locale.color}(i, j, col):
 def ${locale.text}(i, j, text):
     grid.text(i, j, text)
 
+
 def ${locale.fill}(col):
     grid.fill(*col)
 
 def ${locale.clear}():
     grid.clear()
 
+
 def ${locale.line}(i, col):
     grid.line(i, *col)
 
diff --git a/scripts/locale.js b/scripts/locale.js
index 1870f3a..97383f6 100644
--- a/scripts/locale.js
+++ b/scripts/locale.js
@@ -51,7 +51,7 @@ export function addLocale(locale) {
     let result = '';
     for (const key in locale) {
         if (Object.hasOwnProperty.call(locale, key)) {
-            result += `${locale[key]} = ${key}\n`;
+            result += `${locale[key]} = globals().get("${key}", None)\n`;
         }
     }
     return result;
diff --git a/scripts/runner.js b/scripts/runner.js
index 9009d5b..c6236b1 100644
--- a/scripts/runner.js
+++ b/scripts/runner.js
@@ -99,7 +99,7 @@ class Runner {
 
         // Parse the interval: use the localized variable name.
         // NOTE: use the code metadata instead.
-        let interval = this.get('interval', LANG);
+        let interval = this.get('interval', LANG) || this.get('interval');
         if (interval)
             this.interval = interval;
 
@@ -143,6 +143,7 @@ class Runner {
             let locale = getLocale(lang);
             varName = locale[varName];
         }
+        if (!varName) return null;
         return this.globals ? this.globals.toJs().get(varName) : null;
     }