Prototyping interactive objects with personal fabrication tools like 3D printers requires the maker to create subsequent design artifacts from scratch which produces unnecessary waste and does not allow to reuse functional components. We present Interactive Tangrami, paper-folded and reusable building blocks (Tangramis) that can contain various sensor input and visual output capabilities. We propose a digital design toolkit that lets the user plan the shape and functionality of a design piece. The software manages the communication to the physical artifact and streams the interaction data via the Open Sound protocol (OSC) to an application prototyping system (e.g. MaxMSP). The building blocks are fabricated digitally with a rapid and inexpensive ink-jet printing method. Our systems allows to prototype physical user interfaces within minutes and without knowledge of the underlying technologies. We demo its usefulness with two application examples.