Ford circles are parameterized by the rational numbers but are also the
result of an iterative geometric procedure. We review this and introduce an
apparently new parameterization by solutions of a certain quadratic Diophantine
equation. We then generalize to Eisenstein and Gaussian rationals where the
resulting "Ford spheres" are also the result of iterative geometric procedures
and are also parameterized by solutions of certain quadratic Diophantine
equations. We generalize still further to imaginary quadratic fields