LensLuotainTargetChoose what becomes observable

Learning to ask without a history dictionary → · New result: learned spike thresholds →

Can a shadow tell two worlds apart?

Two different hidden light patterns illuminate the same wall. Without a useful occluder their signals are almost identical. Edit the mask or ask for a discriminating lens. This is a 1-D geometric explainer, not a real-camera result or a reproduction of the Python benchmark.

1 · Two hidden objects

World A World B. Which one is behind the corner? The camera cannot see them directly.

2 · The wall measurement

Separation / sensor-noise norm: —. Larger means the wall can better distinguish the two worlds at fixed noise.

3 · Design the observer's question

Gold cells block rays at an intermediate plane. The mask changes the linear measurement operator A, not the hidden object. Click cells to redesign it.

What this proves—and does not prove

With fixed known geometry, another mask can expose image differences that the unmasked view nearly erases. The selection button chooses a mask using both candidate predictions, without using an unknown truth label; this is an illustrative oracle candidate set. This little page has no inverse solver, no real camera access, no sensor calibration, and no learned AI. The tested model, randomized candidate trials, frozen gates and results are in the repository.