The following picture is from the Wikipedia article on Möbius transformation.
It is explained under the picture that
Pre-images of the unit circle are circles of Apollonius with distance ratio $c/a$ and foci at $−b/a$ and $−d/c$ . For the same foci $−b/a$ and $−d/c$ the red circles map to rays through the origin.
I don't understand what this means. Would anyone elaborate how is this picture formed and how it is related to the Möbius transformation?
