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An automated stacking crane must empty a container yard in a fixed retrieval order, but containers arrive stacked in whatever order the ship unloaded them — so the target container is often buried under others that must be relocated out of the way first. This simulator plays out the real algorithm terminal operators use to decide where each blocking container should go: a greedy heuristic that only relocates onto a stack whose top container will be needed later, so the move never has to be undone. Toggle to the naive strategy to see how many extra relocation moves — and crane time — that single rule saves, tracked live as retrieved count, total relocations, and moves per retrieval.