Two angular fields with identical witness readings

Computational companion to Geometry information and approximation cost in recessed-aperture transport, working revision 9 (DOI 10.5281/zenodo.23985228). Two ideal equal-flux fields produce identical open and shifted-aperture witness readings while a third aperture transmits 80% and 50%. A separate construction puts the same approximate record on opposite sides of a 0.010 absolute error limit. The note distinguishes these identifiability results from a conditional 2,000-record synthetic replay saving 361 bytes on first use. The accompanying archive contains exact-arithmetic checks and replay files for byte accounting. Physical measurements are reserved for separate work.