Geometric series geometry: Sankara's contribution

Ancient and medieval Indian mathematicians were fond of validating arithmetic and algebraic truths using geometrical diagrams. Their geometrical imaginations prompted them to view even the progressive series through geometric figures called sredhiksetras. Geometrical exposition of various arithmetic series can be had from several works, but geometric demonstration of geometric series is a special feature of the Lilavati commentary Kriyakramakari by Sankara and Narayana. Sankara has described an interesting geometrical demonstration for summation of a geometric series with common ratio 4. Sankara's demonstration is expounded in modern terms and an attempt is made to generalize it.