META-LEGO will bring the knowledge needed to design metamaterials/classical-materials structures that control elastic waves and recover energy. For this, I will develop, implement and validate a new paradigm for finite-size metamaterials’ modeling, by leveraging the relaxed-micromorphic model that I have contributed to pioneer. The presence of boundaries in metamaterials strongly affects their response when coming in contact with mechanical loads. Yet, we still lack an exhaustive model to predict the static/dynamic response of finite-size metamaterials: current homogenization methods are unsuitable to provide a coherent transition from infinite- to finite-size metamaterials modeling. This prevents us from exploring realistic structures combining metamaterials’ and classical-materials’ bricks of finite size. META-LEGO hypothesizes that the mechanical response of finite-size metamaterials can be explored going beyond classical homogenization. Instead, I will create an elastic- and inertia-augmented micromorphic model with embedded internal lengths to describe the main metamaterials’ fingerprint characteristics, such as anisotropy, dispersion, band-gaps, size-effects, etc. To provide this paradigm shift, I will focus on 4 objectives: 1. Model metamaterials’ response under static/dynamic loads 2. Implement the model on infinite-size metamaterials 3. Validate the model on finite-size metamaterials 4. Design and manufacture metamaterials/classical-materials structures able to control elastic waves and recover energy The reduced model’s structure (free of unnecessary parameters), coupled with well-posed boundary conditions, will allow us to unveil the static/dynamic response of both real and not-yet-existing metamaterials’ bricks of arbitrary size and shape. Playing LEGO with such bricks, we will be able to design and optimize surprising meta-structures, such as noise- and vibration-controlled railway stations, or meta-cities entirely protected from seismic waves.