Graphical Memes creates data visualization software to enable a deep understanding of complex systems using innovative graphical techniques. Its first product, MetaFlow, is an application for creating flow network diagrams, also known as Sankey diagrams. MetaFlow is an excellent tool for representing the various systems that comprise urban metabolism, including energy, food, water, waste, transportation and communications. MetaFlow diagrams provide a whole-system view that elucidates the dependencies and relative importance of component processes. MetaFlow is also applicable in many other contexts, such as factory planning, Web analytics or finance.