paper-rip.mp3: "Various Paper Sound Effects" by Luckius
Source: https://opengameart.org/content/various-paper-sound-effects
Original: paper_ripped_-_1.mp3
License: CC0 1.0 https://creativecommons.org/publicdomain/zero/1.0/

fireworks.wav: excerpt of "Fireworks, Crackle, A.wav" by InspectorJ (Jonathan Shaw, www.jshaw.co.uk), Freesound.org
Source: https://freesound.org/people/InspectorJ/sounds/328864/
License: CC BY 4.0 https://creativecommons.org/licenses/by/4.0/
Changes: excerpt 0.4-7.8 seconds, reduced volume, fades, WAV conversion.

dice-felt-1.wav, dice-felt-2.wav, dice-felt-3.wav: adapted from die-throw-1.ogg, die-throw-3.ogg, die-throw-4.ogg in Casino Audio 1.1 by Kenney Vleugels (Kenney.nl).
Source: https://kenney.nl/assets/casino-audio
License: CC0 1.0 https://creativecommons.org/publicdomain/zero/1.0/
Changes: isolated contact excerpts, high-frequency damping for felt, shorter decay, volume normalization, fades, WAV conversion.

Lottery machine: motor, plastic-ball impacts and latch sounds are synthesized procedurally in the browser; no third-party recordings are used for these effects.

Marble race: gate clicks, ball impacts and finish chime are synthesized procedurally in the browser; no third-party recordings are used for these effects.

Wheel: original procedural wooden clicks, spring snaps and result chimes generated with Web Audio. No third-party recordings.

funnel-contact.wav: adapted from "marble.wav" by jradcoolness, Freesound.org.
Source: https://freesound.org/people/jradcoolness/sounds/334222/
License: CC0 1.0 https://creativecommons.org/publicdomain/zero/1.0/
Changes: first 0.22 seconds, mono, mild frequency filtering, peak normalization and fades, WAV conversion from the public high-quality preview.

funnel-roll.wav: adapted from "Roll Marbles.mp3" by JuandreSound, Freesound.org.
Source: https://freesound.org/people/JuandreSound/sounds/490901/
License: CC0 1.0 https://creativecommons.org/publicdomain/zero/1.0/
Changes: excerpt 2.1-3.3 seconds, mono, low-frequency rolling emphasis, peak normalization and fades, WAV conversion from the public high-quality preview. Played as brief, quiet movement-triggered excerpts, never as a continuous background loop.