"Plastic Tests Plastics" by Richard Moser provides a comprehensive guide to the use and improvement of toy building blocks for constructing a lightweight, cost-effective, and easily reproducible tensile testing setup. This technical book is aimed at professionals and students in the fields of engineering and materials science, covering the characterization of elastomers and stretchable electrodes. Moser explains the underlying theory of material deformation and rubber elasticity, demonstrating how the setup can be used for the mechanical characterization of polydimethylsiloxane (PDMS) with varying stiffness levels. Additionally, the versatility of the device is highlighted through the electromechanical characterization of stretchable thin-film metal electrodes on PDMS. The applications of the setup are diverse, ranging from its use as a teaching tool in practical physics and engineering courses to presentations at scientific exhibitions and its utilization as a cost-effective and reliable laboratory tool.