101.158Mini-project — Generative “Happy Birthday”

Because it is public domain, build a full system.

Identity invariants

• recognizable melody
• phrase 3 is global melodic climax
• phrase 4 resolves clearly to tonic

Global rules

• first statement sparse
• each repetition changes only two dimensions
• borrowed iv used no more than once before ending
• highest register reserved for final statement
• ending thinner than climax

Local rules

• fills only after phrase
• bass mostly stepwise
• melody note may serve as extension
• support voices stay below melody
• if uncertain, melody+bass only

States

ESTABLISH → DEVELOP → THIN → BUILD → CLIMAX → RELEASE.

Perform three versions:

ballad

jazz waltz

swing.

The rule-system remains.