You did not tell me what is the constraint when different size of circles are presented.
Do you want the center of those circles all have the same x-coordinate?
It will be very difficult if you want to use mouse to drag those circles and make them all align by yourself.
The following is the second version which I just add another option for you to adjust the SAME size for all the circles.
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop.
You did not let me know what is the purpose of your project. May be there are better way to achieve it.
Because you did not provide enough information, the above simulation is the best I can do for you!
Please give me DETAIL information if you want me to modify the simulation to better suit your need!