Richard Moser shows how to use and upgrade toy bricks for the construction of a lightweight, low-cost and easy to reproduce tensile testing setup. Tailored for the characterization of elastomers and stretchable electrodes, the setup is capable of performing stress-strain studies along with resistance-strain measurements. Based on the underlying theory of material deformation and rubber elasticity, the author applies the setup to mechanically characterize polydimethylsiloxane (PDMS) with different grades of stiffness. The versatility of the device is highlighted with the electromechanical characterization of stretchable thin film metal electrodes on PDMS. Applications of the author´s setup range from using it as an educational tool in practical physics and engineering courses over being showcase in scientific exhibitions to its utilization as an inexpensive and reliable laboratory tool.