C# Code to drop a rect on to another rect in windowsphone7

Question

Hi,

I am doing this app for windows phone7 in c#

can anyone give me the sample to drop a rectangle on to another rectangle and check if the rectangle is dropped correctly or not.

If not then it should come  to its original position.

Check if rectngle is dropped on a correct rectangle(there will be 4 rectangles).

Please help me

Thanks