I must write a program in WPF. It will be a visualization. When user starts the program, the small circle appears on the screen. When he/she click on it, the textbox will appear and the user will have to write a number. Then the circles in number given by user have to appear around the 'main' circle. The next steps are the same for the other circles ( the next circles appear around the given circle ).

I think that if I had a redraw event in which I could iterate through all circles, making this program would be much simplier. Is there any such event in WPF?
The next problem is that when I create a new ellipse - I cannot make a event for it....
Do You have any ideas how to solve my problems?