Shadow Duet
Pair two shadow voices by supplied frequency ratio or interval key and assess harmonic compatibility under an explicit toy ranking (simpler integer ratios preferred). Not a universal music-theory claim. Audio provides symbolic tones with exact text alternatives.
Original toy model of interval ratios and compatibility. Audio symbolic tones with exact text alternative. Not real music theory instruction. Graphs list every valid link; matches reuse targets only when semantically identical by rule.
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