private void btn_BottomLeft_Click(object sender, EventArgs e)
        {
            withinTimer.Interval = intIntervalRequired;
            if (!withinTimer.Enabled)
            {
                rtxt_WordBuilder.Text += "*";
                withinTimer.Start();
            }
            else
            {
                string lastChar = "";

                // Gets the last character
                if (rtxt_WordBuilder.Text.Length > 0)
                {
                    lastChar = rtxt_WordBuilder.Text.Substring(rtxt_WordBuilder.Text.Length - 1, 1);
                }


                // Deletes the last character
                rtxt_WordBuilder.Text = rtxt_WordBuilder.Text.Substring(0, rtxt_WordBuilder.Text.Length - 1);

                // reset timer
                withinTimer.Stop();
                withinTimer.Start();
                // depending on last char, pick new one
                switch (lastChar)
                {
                    case "*":
                        rtxt_WordBuilder.Text += "-";
                        break;
                    case "-":
                        rtxt_WordBuilder.Text += "_";
                        break;
                    case "_":
                        rtxt_WordBuilder.Text += "*";
                        break;
                }
            }
        }