Aerial Crowd Figure-Ground Reversal Prompt

Anchor: A near-nadir aerial photograph of [CITY]'s [GATHERING - market / beach / festival / plaza / stadium concourse], densely packed with people, in which the bare ground left unoccupied forms the unmistakable shape of [REGION - a face in profile / a single word / a hand / a bird / a letterform] ::4 Perceptual Mechanism: Figure-ground reversal at a density threshold. Above roughly 2 people per square metre the crowd stops reading as individuals and becomes TEXTURE; the void is then read as FORM. Recognition must arrive one beat LATE - the image is a crowd photograph first and a shape second. Void occupies 20-35% of frame; above 45% the crowd becomes the ornament and the effect inverts ::4 Morphology: The void contains NOTHING - no paint, no tape, no barrier, no stage, no marked line, no security cordon. The shape is defined solely by where bodies are and are not. Boundary must be crowd-plausible: ragged at the scale of one or two people, clean and unambiguous at the scale of the whole frame. Stray individuals may stand just inside the edge - perfect edges look like compositing ::3 Material Physics: Real ground substrate - AI_INFER([CITY] → wet asphalt / pale sand / granite setts / red dirt / painted court). Crowd clothing must be maximally VARIED in hue and value; uniform clothing converts texture into pattern and kills the reversal. Include prams, umbrellas, bicycles, market stalls, and 2-3 people in motion blur ::3 Illumination: High sun, short shadows, near-vertical camera. Long raking shadows will spill across the void and destroy the boundary. Overcast flat light is the safe fallback ::2 Viewing Protocol: Must resolve as a shape at 200px thumbnail AND survive a 100% zoom, where every individual must still read as a photographed human being ::2 Render Stack: documentary aerial photography, drone at 120m, 50mm equivalent, photojournalism colour, no post-processing look ::1 Failure Condition: One painted marking, one barrier, or one visible stage turns this from an illusion into a publicity stunt. Symmetrical or geometric crowd distribution turns it into a render ::-1 Negative: [ground paint, tape, cordons, barriers, stage, uniform clothing, matching colours, symmetrical arrangement, CGI crowd duplication, tilt-shift, HDR, oversaturation, text, watermark, visible drone, motion smear across whole frame] ::-1