This slide show describes an innovative design to add interactivity, sensors, and microcontrollers to the existing paradigm of Lego systems.  The key feature is the interchangeability of parts and components, just as Lego is built on the idea of interchangeability of static plastic elements.  The basic idea is to take existing Lego parts, primarily simple 1x2, 2x2 and 2x6 blocks and cleanly mill a slot that is the right size to accomodate various components, all of which would be custom designed on printed circuit boards of a uniform thickness, and with a uniform area around the outside of the board unencumbered by sub components, so that they can easily be slid into a slot, contained and added to any Lego structure.  Components would be connected via custom wires that snap into connectors on the individual component boards.