Computerized Adaptive Testing: 2D Ability Trajectory & Information Field

This is a genuine, independently-computed 2D counterpart to the 3D item-response-engine simulator. Instead of rendering each item as a 3D bar positioned by difficulty, it plots the actual functions the adaptive engine reasons about: every bank item's 3-parameter-logistic item characteristic curve across the whole ability axis, the bank's aggregate Fisher information field showing where measurement is most precise, and a running trajectory of the Bayesian expected-a-posteriori ability estimate with its shrinking standard-error band as items are administered one by one — a convergence history the 3D scene, which only ever shows the current instant, has no way to display. Tune the bank size, guessing floor, the simulated examinee's true ability and the stopping standard-error threshold to watch the curves, the information peak and the estimate trajectory respond — the same underlying 3PL item-response and Bayesian-update math as the 3D page, recomputed from scratch and shown through views the original never exposes.