Extended Producer Responsibility: 2D Waste Hierarchy Funnel

This is the 2D companion to the 3D Extended Producer Responsibility simulator. It keeps the exact same multinomial-logit discrete-choice physics — the standard tool environmental economists use to predict how producers and waste handlers actually route material once fees and subsidies change the relative cost of each option — but renders the waste hierarchy as a side-view funnel of stacked bands (Reduce narrow at top, Landfill wide at the base) instead of a 3D pyramid, computed independently from scratch rather than flattened from the 3D scene. A continuous stream of end-of-life product particles falls from the source and is routed band-to-band by the same cost model; where each particle lands is sampled live, never scripted. Raise the Extended Producer Responsibility fee and watch the fee-funded subsidy pull mass up and away from Landfill and Recover; raise the eco-design score and see Reuse and Recycle become cheaper on their own merits; lower the collection rate and a share of the stream leaks out before it ever reaches a bin. Unlike the 3D version's orbit camera, this view supports direct drag-to-pan and scroll-to-zoom over the funnel itself. Live readouts track landfill diversion, a circularity index, and the cumulative EPR revenue funding the whole system.