在几秒钟后，在控制台窗口中生成一行的方法会消失吗？

I need to basically flash a set of numbers for roughly 2 seconds. The user will then have to remember the numbers and type them. How can I do this? I have tried to use a timer or changing the color of the text to the same color of the background, but I can't think of a better way of doing so. Any suggestions?I need to basically flash a set of numbers for