In this article, we describe a novel hardware platform aimed at the realization of cellular architectures. The system is built hierarchically from a very simple computing unit, called ECell. Several of these units can then be connected, using a high-speed serial communication protocol, to a more complex structure called the UltraStack. Consisting of four different kinds of interconnected boards (computational, routing, power supply, and display), these stacks can then be joined together to form an arbitrarily large parallel network of programmable circuits. This structure, while theoretically universal in its operation, is however particularly suited for the implementation of cellular computing applications.