Pickaxe.Program.Border C# (CSharp) Method

        private static string Border(List<int> lengths)
        {
            var topBottom = new StringBuilder();
            for (int x = 0; x < lengths.Count; x++)
            {
                topBottom.Append("+");
                for (int len = 0; len < lengths[x]; len++)
                    topBottom.Append("-");
            }
            topBottom.Append("+");
            return topBottom.ToString();
        }