waterfall development because a graphical depiction of how stages are completed over time cascades from top left to bottom right. Stages typically include: 1. Concept exploration, culminating in documenting user stories and perhaps a lightweight business plan that makes the business case for the work 2. Prototype or product specification, the document or wireframe prototype that provides guidance on proposed product functionality, which allows engineers to begin 3. Design work, which in turn is followed by 4. Product development 5. Internal testing 6. An alpha launch with pilot customers
