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let $$M = \left\{(x, y) \epsilon R \times R ∶ x^{2} + y^{2} \leq r^{2} \right\}$$

where r > 0. Consder the geometric progression $$a_{n} = \frac{1}{2^{n-1}}, n = 1, 2, 3, ...$$ Let $$S_{0}=0$$ and, for $$n \geq 1$$, let $$S_{n}$$ denote the sume of the first n terms of this progression . For $$n \geq 1$$, Let$$C_{n}$$ denote the circle with center $$\left(S_{n-1},S_{n-1}\right)$$ and radius $$a_{n}$$.