Our research aims to explore the fundamental interaction between waves and matter by tackling the problem of designing material basic building blocks (i.e., unit cells) with properties that do not exist in nature (i.e., metamaterials). These building blocks can be programmed to be either passive (i.e., have unprecedented properties through architecture) or active (i.e., change their intrinsic properties in response to an external stimuli). A few examples are the design of the first purely acoustic transistor [Bilal et al., PNAS 2017], the first 3D topologically insulated/protected metamaterials with intrinsic elastic polarity [Bilal et al., Adv. Mater. (1) 2017] and a metamaterial that can guide stress waves by changing its dynamical characteristics on the fly [Bilal et al., Adv. Mater. (2) 2017]. The research nature is highly multidisciplinary spanning mechanical and aerospace engineering, computer science, condensed matter physics and material science.