the set of points with <at> distance 1 from K
the set of points at a distance less than 1 from K
Hence A and B are at distance precisely d.
Consider a pair of points a, b at distance 1.
The point p is within distance d of X.
Their centres are a distance at least N apart.
Any point not in B is moved by f a distance equal to twice the distance to M.
If we stay a fixed distance off the critical line, we do not expect Benford behaviour.