Knock-On - drop one what-if into a world and watch it ripple

Write one speculative change - a what-if - pick the parts of life to follow (daily life, work and money, law and power, home and family, language and culture, belief and ritual, tools and tech, land and nature) and how fast it arrives, and jot any knock-ons you already have in mind. Free in the browser: the premise check, the pond (the change as a stone, three rings, one sector per domain, your own knock-ons placed on it) and every export. Two metered lanes: trace the ripples - spreads (up to fourteen effects over three rings, with tensions and story hooks), fizzles (why it stays small, plus a bigger version to try) or sharpen it (decisions to make first) - or pick one knock-on and get found documents from inside that world, each with a placard naming what its writer cannot see. The page re-checks every reply. Speculative fiction, not forecasts. Built on @jwynia/systemic-worldbuilding and @jwynia/oblique-worldbuilding.