Using the pre-provided tone.min.js (global Tone), build a clickable pentatonic pad grid that triggers a synth voice with reverb, plus a play/stop button that runs an arpeggiator sequence at an adjustable tempo. All sound synthesized, no audio files.

We need build single-page web app and write it ALL into one self-contained file named index.html in current directory: CSS in <style> tag, JS in <script> tag, inline — do not create separate .css/.js files. Use NO external resources, CDNs or network requests: artifact runs fully sandboxed with no network. End with index.html present. These library file(s) are ALREADY present in current directory — load each with a plain <script src="NAME"></script> using its exact filename (never a CDN or URL), then build on top of it: tone.min.js.

Current working directory /tmp/ws

First check if tone.min.js exists.

Exists.

We need build index.html with script src="tone.min.js". Need clickable pentatonic pad grid. Pentatonic scale. Probably 5 notes per octave? Grid? Maybe 5x? Let's design a 2-octave pentatonic pad grid: 10 pads? Pentatonic minor? Let's choose C minor pentatonic: C Eb F G Bb. Or major pentatonic.

Clickable pad grid triggers synth voice with reverb.

Play/stop button runs arpeggiator sequence at adjustable tempo.

All sound synthesized.

We need to use Tone.js. Use PolySynth? Use Synth with Reverb.

Tone.js needs user interaction to start AudioContext. Clicking pads will start.

Pentatonic pad grid: maybe 5 columns for notes, 2 rows for octaves? Or a grid 5x2 =10 pads.

Arpeggiator sequence: use Tone.Sequence or Tone.Loop? Or Tone.Arpeggiator? Tone has Arpeggiator effect? There's Tone.Arpeggiator class. Actually Tone.Arpeggiator is a transport-based arpeggiator. Or use Tone.Sequence with notes.

Simpler: Have an array of notes from pads that are active? Or run arpeggiator over pentatonic scale.

Probably arpeggiator plays up/down sequence over selected root? Could be fixed C minor pentatonic.

Tempo adjustable via slider (BPM). Play/stop button toggles Transport.

Need UI: grid of buttons, each with note name. On click, trigger synth with reverb. Maybe also show active.

We need CSS styling.

All in one file.

Make sure script src="tone.min.js" before our script.

Implementation plan:

HTML structure:
<div id="app">
<h1>Pentatonic Pad</h1>
<div id="controls">
<button id="playStop">Play</button>
<label>Tempo <input id="tempo" type="range" min=60 max=180 value=120> <span id="tempoVal">120</span></label>
</div>
<div id="padGrid"></div>
</div>

Style: grid 5 columns.

JS:
const Tone = window.Tone;

Create synth: new Tone.PolySynth(Tone.Synth).connect(new Tone.Reverb({decay:2, wet:0.4})).toDestination()
Or use Tone.Synth.

Better: const reverb = new Tone.Reverb({decay:2.5, wet:0.3}).toDestination();
const synth = new Tone.PolySynth(Tone.Synth, {oscillator:{type:'sawtooth'}, envelope:{attack:0.01, decay:0.2, sustain:0.3, release:0.8}}).connect(reverb);

Pentatonic notes: define root = 'C4'. Pentatonic minor intervals: 0,3,5,7,10 semitones. Generate 2 octaves.

Create pads: for octave offset 0,1? Let's make 5 notes x 2 octaves =10 pads.

Grid cells button.

On click: Tone.start() if needed. synth.triggerAttackRelease(note, '8n')

Arpeggiator: Use Tone.Sequence or Tone.Loop. Simpler: create a sequence with notes array (pentatonic scale ascending). Play pattern.

Use Tone.Transport.bpm.value set.

Play/stop toggles Transport.start() / stop().

When play, start arpeggiator sequence that loops.

We can use Tone.Sequence with time '8n' and notes.

Define notes array for arpeggiator: maybe all pads notes in order.

Better: when play, we run sequence over the pentatonic notes starting from C3 to C5.

Could allow adjustable pattern: up down.

Implement simple arpeggiator: notes = pentatonic scale repeated.

Sequence: new Tone.Sequence(time, callback, notes). Start.

Need to stop on stop button.

Also need to ensure Tone.Transport starts.

Implementation details:

const pentatonic = ['C','Eb','F','G','Bb']; intervals.

Build notes: for octave in [3,4,5]? Let's choose 3 octaves?

Pad grid maybe 5 columns x 3 rows? Hmm.

Simplify: 5 pads per octave, 2 octaves =10 pads.

Let's generate:
root = 'C'
notes = []
for oct=3..4:
 for i in [0,3,5,7,10]:
   note = Tone.Frequency(`${root}${i}?...`) Wait Tone.Frequency can take note name with accidental.

Better build note names manually: ['C','Eb','F','G','Bb']

For each octave, map: C3, Eb3, F3, G3, Bb3, C4, Eb4...

Yes.

Create pad elements with data-note.

On click: synth.triggerAttackRelease(note, '8n')

Arpeggiator sequence: use same notes in order.

But if tempo changes, update Tone.Transport.bpm.value.

Play button: if playing, stop transport, set text to Play else start.

Need to ensure Tone.start() on first interaction.

Maybe init on first click.

Let's also add visual feedback: active class.

Potential issue: Tone.Reverb requires async warm up. Need reverb.generate()? In Tone.js, Reverb needs to be loaded. Could just use Tone.Reverb and then await reverb.ready.

Simpler: Use Tone.JustInTime? Might be okay.

Alternatively use Tone.Freeverb for instant? Could use Reverb but need warm up. We'll just create reverb and assume it works.

Better to use Tone.FeedbackDelay? But spec says reverb.

We can create reverb with decay and wet. Might need to wait.

Let's create reverb = new Tone.Reverb({decay:2, wet:0.4}); reverb.toDestination(); Then synth.connect(reverb). Might be okay.

Alternatively use Tone.Chorus? No.

We'll proceed.

Make index.html.

Need to ensure script loads tone.min.js first. So <script src="tone.min.js"></script> then <script>...</script>

All inline.

Make CSS nice.

Implementation details for Tone.Sequence:

const arpeggiator = new Tone.Sequence((time, note) => {
  synth.triggerAttackRelease(note, '16n', time);
  // flash pad
}, notes, '8n');
arpeggiator.loop = true;

On play: Tone.Transport.start('+0.1'); arpeggiator.start(0)

On stop: Tone.Transport.stop(); arpeggiator.stop()

Adjust tempo: tempo slider input event -> Tone.Transport.bpm.value = val; update span.

Also need to ensure transport starts after user interaction.

Edge: If user clicks pad while transport running, okay.

Potentially need to set Tone.Transport.schedule.

Ok.

Create file.

Let's write index.html.

File written. Should verify exists.

Done.

We should output summary.