Chain of Thoughts prompt

METER: 2/4

TITLE
Bar 2 — Two tutti verticals from two fresh register-partitioned aggregates (contrast with Bar 1).

INSTRUMENTS (EXACT)
Use these six instruments and no others:
[alto_flute, bass_clarinet, trumpet, violin, cello, double_bass].
Every instrument must sound on BOTH verticals; still monophonic per instrument.

MUSICAL TECHNIQUE (WHAT TO CONSTRUCT INTERNALLY — DO NOT PRINT IT)
Design two distinct register-partitioned, non-isomorphic aggregates, call them A and B. Realize them purely via PT design (pitch/time/duration/velocity). Do not output the aggregates — only the PT bundle.

Aggregate A and B (both must satisfy):
• Partition register into three contiguous bands (LOW / MID / HIGH) over the playable MIDI range.
• Assign to each band a disjoint pitch-class set (pcs) of exactly 4 pcs; LOW_pcs ∪ MID_pcs ∪ HIGH_pcs = all 12 pcs (0..11).
• The order of pcs within each band matters (defines neighborhood for targeting), and the pcs should suggest thirdal/quartal neighborhoods (avoid trivial equal-step cycles like 0–3–6–9).
• A and B must be different (at least one band uses a different pcs set and/or different band spans).
• Contrast with Bar 1 (choose pcs so the sonority palette is perceptibly different). Even though earlier PT JSON is visible in the reference context, do not copy Bar-1 sets—design new A and B.

VOICING RULES (HOW TO REALIZE THE TWO HITS WITH PTs)
We will create exactly two simultaneous verticals (tutti chords) at relative bar ticks 0 and 4, each with duration 4 ticks (quarter notes on a 1/16 grid). No other notes in this bar.

For EACH instrument:
1) Determine its band for voicing by using the instrument’s tessitura center (LOW/MID/HIGH).
2) Hit 1 (tick 0, dur 4): choose one pitch-class from Aggregate A’s pcs for that band, then snap to the nearest legal MIDI inside the instrument’s range around tessitura center.
3) Hit 2 (tick 4, dur 4): choose a pitch-class from Aggregate B’s pcs for that band, not equal to the first hit’s pc for that same instrument; target a nearby register (±3 semitones window is fine), then snap to the nearest legal MIDI inside range for Aggregate B.
4) Avoid unisons across adjacent instruments on each hit (mild constraint); octave doublings are acceptable but keep them sparse.
5) Keep voicings center-weighted (db/cello anchor LOW, bcl/cello share LOW↔MID, vn/af/tpt occupy MID↔HIGH).

DYNAMICS
Two fixed dynamic levels for clarity of contrast:
• Hit 1 velocity ≈ 124 (stronger)
• Hit 2 velocity ≈ 114 (slightly softer)

Context rule: When later prompts ask to recall Bar-2, they will copy from this bar’s PT JSON in the reference context; keep your bundle clean and unambiguous (one feature per instrument, simple single-step time pattern to [0,4]).

PT REALIZATION REQUIREMENTS (so the bundle reproduces the behavior)
• TIME: strictly increasing using only `add {1,2,3,4}`. For exactly two onsets at 0 and 4, use a single-step pattern that yields `[0,4]` (e.g., seed time=0, transforms `[{"name":"add","args":[4]}]` with `N=2`). No zeros; no mul/div.
• DURATION: constant 4; values must stay in `{1,2,3,4}` and obey MAX(duration) ≤ s_min (here `s_min = 4`).
• PITCH: add/sub only. Realize the two chosen targets by setting `seed pitch = Hit1_MIDI` and a single transform whose delta lands exactly on Hit 2 (delta = Hit2_MIDI − Hit1_MIDI).
• VELOCITY: two values `[124, 114]` (e.g., e.g., seed 124 then subtract 10).
• METER: seeds must set numerator=2, denominator=4; numerator/denominator transforms are constant `add 0`.

TEXTURE CHECKS
• Exactly two notes per instrument; both verticals are tutti; no extra events.
• All MIDI pitches must be inside each instrument’s hard range and on a band-legal pcs for the respective aggregate and register.
• Notes must end at or before tick 8.

FORM FOR THIS PROMPT
Return one bundle with exactly six features (one per listed instrument) and a run_plan that produces:
– time onsets `[0,4]`,
– duration `[4,4]`,
– pitch realized from Aggregate A then B as above,
– velocity `[124,114]`,
while respecting the PT op constraints.