Since Euler’s development of the Tonnetz in 1739, musicians, composers and instrument designers have been fascinated with the concept of musicalisomorphism, the idea that by arranging tones by their harmonic relationships rather than by their physical properties, the common shapes of musical constructs will appear, facilitating learning and new ways of exploring harmonic spaces. The construction of isomorphic instruments, beyond limited square isomorphisms present in many stringed instruments, has been a challenge in the past for two reasons: The first problem, that of re-arranging note actuators from their sounding elements, has been solved by digital instrument design. The second, more conceptual problem, is that only a single isomorphism can be designed for any one instrument, requiring the instrument designer (as well as composer and performer) to "lock in" to a single isomorphism, or to have a different instrument for each isomorphism in order to experiment. Musix (an iOS application) and Rainboard (a physical device) are two new musical instruments built to overcome this and other limitations of existing isomorphic instruments. Musix was developed to allow experimentation with a wide variety of different isomorphic layouts, to assess the advantages and disadvantages of each. The Rainboard consists of a hexagonal array of arcade buttons embedded with RGB-LEDs, which are used to indicate characteristics of the isomorphism currently in use on the Rainboard. The creation of these two instruments/experimentation platforms allows for isomorphic layouts to be explored in waysthat are not possible with existing instruments.