These are the orthographic rules for where to when to write the tilde, viewed from the other side. This has only a tenuous connection to how the stresses are ac

These are the orthographic rules for where to when to write the tilde, viewed from the other side. This has only a tenuous connection to how the stresses are actually distributed—while placing stress before the last stem consonant is indeed the most common noun stress pattern, e.g. verb inflections are a lot more all over the place; if you pull up a typical conjugation table, some half of the entries need explicit accents because they don't follow these rules. The choice of which patterns to designate as default and which to write with accents is honestly kind of arbitrary. One can easily imagine an alternate universe where the standard orthography allocates accents by counting vowel letters instead of syllables, or with the slightly more synchronically opaque "last stem consonant" formulation, or one where coda n is formally regarded as a vowel—this doesn't require an AU, actually, just compare orthographies with the other Iberian Romance standards. (There's this one particularly notable pattern where final syllables with high vowel nuclei are almost always stressed in native vocav, which e.g. occurs reliably in 1st-person preterite conjugations. They're written with the tilde anyway, but it didn't have to be this way; no hispanophone sees "recibi" and entertains the possibility that it might have grave stress, that would sound unnatural even if they can't point out exactly what's wrong with it.)