The idea for mexdulon tetra-Boards arose when I occupied myself closer with digital electronics and microprocessor technology. In class everything is treated very theoretically, what makes it hard to understand. Although there are teachers who use simulation software, in order to teach the subject to students. However, some training is necessary, the software is not freely available (and thus can not be used at home), and the whole is only virtually. One possible alternative were breadboards, but who wants to use a few more ICs, will find that the space requirements and effort for building rise immensely. Also here the risk is high to have made a mistake in the wiring, or even to create a short circuit. In this way experimenting with digital technology is no fun. From this background, I designed mexdulon tetra-Boards, a modular system for the construction of digital circuits.