Fix

cgi-bin/uebung08/hangman.php

@@ -20,7 +20,7 @@ END;
     $alphabet = range('A', 'Z');
     foreach($alphabet as $abc) {
 echo <<<END
-        <button name="$abc" type="submit" value="$abc">$abc</button>
+        <button name="letter" type="submit" value="$abc">$abc</button>
 END;
 
     }