{
  "schemaVersion": 1,
  "slug": "hourglass-grain-neck-pile-transfer",
  "ownerPath": "/templates/hourglass-grain-neck-pile-transfer",
  "semanticKey": "discrete grains leave an upper bed through one fixed neck and build a lower pile",
  "demand": {
    "type": "independent-product-lookup-value",
    "historicalExactQuery": null,
    "exactSearchVolume": null,
    "rationale": "Connect a shrinking granular bed with a growing deposit through a visible narrow passage. Unlike two liquid levels moving together, the new lower material must arrive as separate grains through the neck and accumulate underneath it. The goal is a qualitative transfer, not a clock.",
    "status": "author-proposed; independent admission pending"
  },
  "input": "first-frame.png",
  "inputRoles": {
    "first-frame": "one authored PNG",
    "last-frame": null,
    "guide": "review only; do not upload"
  },
  "constraints": [
    "The same vessel outline, open neck and floor remain fixed.",
    "The first visible transfer enters and exits the original neck.",
    "Falling material remains granular rather than changing into a liquid sheet.",
    "The upper bed recedes while the lower deposit grows during the same interval.",
    "New lower material appears beneath the outlet through visible arrivals, not as an instant full pile.",
    "The ending keeps grains above and a smaller deposited pile below without inversion or exterior leakage."
  ],
  "steps": [
    "Find the lowest upper grain and the still-empty neck. The source must have an open passage; do not begin with a closed stopper and ask material to pass through it.",
    "Request partial drainage only, leaving material visible in the upper chamber. Keep the neck fixed and ask for a narrow intermittent succession of grains instead of a solid liquid column.",
    "Review a grain entering the neck, grains leaving it and the lower pile rising beneath that exit. Compare upper loss and lower growth over the same interval, without claiming a calibrated mass balance from projected dots."
  ],
  "nearestOwners": [
    "/templates/connected-vessels-level-equalization",
    "/templates/two-droplet-contact-coalescence"
  ],
  "substantiveDifference": "The connected-vessel page follows two liquid surfaces and an opening valve; the droplet page joins two outlines into one. This task keeps discrete material identity through a fixed constriction and creates a deposit from arrivals. It does not sort two size classes like the sieve exercise.",
  "modelExecution": {
    "performed": false,
    "taskId": null,
    "result": null,
    "paidCalls": 0
  },
  "sourceType": "original-local-deterministic-illustration",
  "rights": "Original authored geometry and prose; no third-party media. Independent review pending."
}