Originally, City is an enormous and intricate system. However, Cerdá simplified the complicated system into a
basic unit, the Manzana, which is the unique code belonging to Barcelona found by Cerdá and based on his
analysis to the history of the city, life of its citizens, and some other cases. Being at the core of Barcelona
Eixample plan, it gradually formulates the enormous city system of Barcelona and thus paves the way for its
future development. Starting with the rules of Invariability, Simplicity and Changeability, the three principles in
Yi, this thesis regards the Manzana as a Yin-Yang body, with Yin and Yang power complementing and
coexisting with each other. By restoring the codes hidden behind the 550 Manzanas in Barcelona, the thesis
tries to explore the common ground between the physical space of the city and the binary life of the people
living in it.Peer Reviewe