Each of the 17 goals holds a progress value (0–100%). Edges encode documented SDG interlinkages: synergy edges (e.g. Clean Water → Good Health, Clean Energy → Climate Action) mean progress on one goal tends to lift the other; trade-off edges (e.g. Economic Growth vs. Climate Action, Zero Hunger vs. Life on Land) mean progress on one tends to strain the other.
Drag a goal's slider, then press Propagate effects — the change from baseline ripples one hop along every edge (synergy pushes neighbours up, trade-off pulls them down), and the wave animates across the network. Press it again to let the ripple travel further.