How to make panel in tkinter or which widget will be used to hide and show checkbox?

I am not sure, I understand this sentence.

Something about the keywords "widget" and "hide"

http://effbot.org/tkinterbook/pack.htm#Tkinter.Pack.pack_forget-method

Hello!

This is not a python question. It is a windows one.

[url]http://support.microsoft.com/kb/307859[/url]
[url]http://www.informit.com/articles/article.aspx?p=415193&seqNum=6[/url]

If you have found a simple solution, please share it.

I have found some games.

You must add the paddle's momentary velocity to the pucks velocity-1 in a vectorial way.
That means if the paddle is not moving, then the velocity of the puck after the hit is -1
velocity before the hit. As expected.