Eco-efficiency begins with the assumption of a one-way, linear flow of materials through industrial systems: raw materials are extracted from the environment, transformed into products, and eventually disposed of. In this system, eco- efficient techniques seek only to minimise the volume, velocity, and toxicity of the material flow system, but are incapable of altering its linear progression. Some materials are recycled, but often as an end-of-pipe solution, since these materials are not designed to be recycled. Instead of true recycling, this process is actually downcycling, a downgrade in material quality, which limits usability and maintains the linear, cradle-to-grave dynamic of the material flow system.