You run the kingdom's spice desk. Three counsels put forward three demand curves — drawn in full on the board. Exactly one is the market's truth, and any price between 1 and 16 kr may be posted, as often as you please.
But the market has a daily bustle: a reading is true demand plus a nuisance of at most 4 either way — any amount within that, never more. A curve is struck only when a reading contradicts it beyond the bustle. So where two curves sit more than 8 apart, one experiment must expose the impostor; a smaller gap is a gamble — the wider the gap, the better the odds; and curves that never drift more than 8 apart can never be told apart with certainty — though patience and dice may yet deliver them.
The board keeps its own counsel: no curve is ever marked struck while you play. The readings are the data; the reckoning is yours. Only the verdict shows what survived.
When ready, publish: back a counsel — or rule that no price can force a verdict. A proven “cannot” pays like a conviction. A guess that merely fits pays nothing; neither does surrender while proof is still available.