Click an element to select it, then insert after it. Every operation does a constant amount of work: one insertion, a few split moves, and a few steps of the top-level job. Watch where that work goes.
Apply and replay reruns the same operations under the new parameters. Values below the thresholds of
docs/SPEC.md §7.1 (for example KG = 1, s ≤ 4, small β) can make guards fail. The structure then
falls back to a synchronous rebuild, and answers stay correct.
Bottom row: the elements in list order (H is the head sentinel). Above it, the groups, which split once
they reach G elements, and the chunks, whose thin bar shows the fill against capacity T, with the red tick at θ = ⌊2T/3⌋.
A quiet chunk above θ waits in the priority queue. The reservation process takes the fullest one, places two fresh
chunks around it, and starts a top-tree job. The rows above the chunks are the top tree, one row per height. Each bar
covers the chunks whose stored path passes through that node, so a ghost (dashed) keeps its bar until the sweep has
re-routed all of them. An element's key is (chunk tag, group label, element label), and order(x, y)
compares keys. Shift-click a second element to try it.