The tune you drew

Build 'The tune you drew' for an invented Sampleton Music Room. Draw an original brass and wood marble instrument with eight tuned bars. The visitor draws an eight note phrase across a small score strip, then watches marbles land on the selected bars in time with that phrase. Each landing and its optional pitched tone must use the same scored event. Add Tempo, eight labelled note sliders, Make another phrase and Low register. Keep the note sliders in a keyboard editing disclosure. Offer an instrument PNG and a MIDI file containing the visitor's eight notes and chosen tempo. Use native controls, readable text of at least 12px, Play, Pause and Reset. Start still with reduced motion. Fit the complete instrument inside the available canvas without cropping, including the popup; let controls scroll on narrow screens. Sound starts off and uses the site's audio helpers, with voices stopped on pause and the context closed when the plate leaves view or unmounts.

1. Store eight scale indices and a tempo. Give the score strip and note sliders the same values, interpolating a touch stroke across any skipped note columns.
2. Schedule one impact per beat. Derive each marble's fall and rebound from its impact time, then trigger the matching bar pulse and tone at that event.
3. Capture dragging on the small score strip only, so a swipe on the main scene still scrolls. Keep the eight sliders available for keyboard editing.
4. Write a format 0 MIDI file with a tempo event, eight note on and note off pairs, and an end of track event. Save the drawn instrument separately as PNG.
5. Contain the whole drawing on resize, start paused for reduced motion, and close optional sound and remove listeners on navigation or unmount.