Rhombus inequalities compare four nearby coefficients of a homogeneous polynomial. A known theorem says that, in three variables, sufficiently strong inequalities force real stability, but its required factor grows with the degree. This anonymous, unrefereed candidate argues that the fixed factor three works in every degree. The proof normalizes the coefficient array, pairs terms by parity, and bounds the resulting multiplicities with two convergent series. The phrase rhombus condition becomes ambiguous in more variables, so the paper tests three precise extensions separately. Coordinate-face inequalities cannot work with any finite universal factor once there are at least four variables. One strict multiplicative exchange rule is internally inconsistent for positive full-support quadratics. A normalized discrete-concavity version is meaningful, but a finite positive family approaching the known Fano obstruction rules it out from seven variables onward. The normalized cases in four, five and six variables remain open. The package includes exact producer replay, hostile mutations, source mapping and internal review. These checks do not establish an independent proof, formal verification, external specialist review, journal peer review or historical priority. The synthetic-voice briefing is a communication aid, not additional mathematical evidence.