So let's say I have a block of code that gets called every second. In this block of code I want to merge two circles into each other, let me illustrate: here

Every second (or 'tick') I want the red circle to move to the blue circle in order to be the exact same size as the blue circle. But, as you can see in the picture, the top-left corner has to cover a lot more distance than the bottom-right corner.

Any idea's on this?

I want to write some code that will "merge" two circles into each other. Let me illustrate:

I want the red circle to move toward the blue circle, in order to have the exact same size and position as the blue circle after, say, $n$ steps. But, as you can see in the picture, the top-left corner has to cover a lot more distance than the bottom-right corner.

Any ideas on this?