Animated Sankey diagram that visualizes the UK's 2012 energy balance—energy production, conversion, and consumption—as a flow of moving particles along curved paths. The interactive visualization combines a D3.js SVG layout of rectangular nodes and cubic Bézier links with an HTML5 Canvas overlay, where the flowing particles are drawn using Canvas arc methods. Particle frequency and size scale with each link’s energy value, while their color interpolates between the source and target node colors.