This project began with previous research into adjustable arch centering. The designer studied the framework for brick arch construction to increase the plasticity, interpreted as formal expressive capability, of brick structures. This project contains two main parts: first is further development of adjustable arch centering with a transformable tool design allowing construction of linear, arched spaces at different heights and radii. The second phase was to apply this tool on a site and program.The design of adjustable centering combines small, adjustable units. To construct a long, arched space requires only 3 layers of the adjustable centering.The designer chose Kat Hing Wai Walled Village as an experimental testing site. Site analysis suggested a small community library as a plausible testing facility. The final design outcome presents the spatial quality of a library designed in linear, arched spaces.