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A person claps in a large empty hall with a hard concrete floor and bare parallel walls. The clap rebounds into a fluttering string of fast repeating echoes that buzzes between the walls for several seconds.

C1-3-21 Steady State · sound_persistence principle: Echo (Wave)
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Per-prompt rubric

Basic standards

Visual presence

  • a person
  • a large empty hall
  • a concrete floor
  • parallel walls

Event: a person claps inside a large empty hall

Audio presence

  • a person

Sound: a hand clap

Key standards

Visual physical commonsense (V-PC)

  • A single person performs a single hand clap inside a large hall.
  • The hall has bare hard parallel walls and a hard floor.

Audio physical commonsense (A-PC)

  • A rapid-repeating flutter pattern of fast clap reflections is audible after the clap.
  • The flutter pattern persists for several seconds before fading.

Cross-modal physical commonsense (AV-PC)

  • The initial clap transient in the audio aligns in time with the visible hand-clap action.
  • The flutter-echo string follows the single visible clap as its consequence.