Bildprompt
Create a vertical abstract optical image at 848:1264, about 2:3. Fill the canvas with a soft upward spreading fan of colored light on warm charcoal brown. The luminous shape is broad across the upper and middle frame and narrows into a blurred rounded green and yellow base around 82 percent height. Its lower end is centered slightly left of the canvas midpoint. Dark charcoal triangular spaces occupy the bottom corners and curve upward along both outer sides. Do not make the fan a physical object or a sharp geometric triangle.
The broad upper region is deep hazy indigo and violet, almost as dark as the background along the very top. Across the middle, large diffuse vertical blue columns run downward, merging into saturated cyan around the central lower half. The left lower edge turns green; the right lower edge mixes teal and muted moss green. Near the bottom, a warm yellow green patch appears within the blurred cyan column, fading into olive then brown without a sharp endpoint. A darker vertical blue trough is subtly visible just right of center. Let the outer light extend beyond the side boundaries around the middle height.
Use heavy optical defocus and gently mottled fine analog grain, with broad continuous gradients and restrained brightness. There are no hard light rays, horizon, reflective floor, projector, glass prism, distinct object edges or stars. Keep the charcoal background and soft indigo, blue, cyan, green and small muted yellow progression. No typography, border, rainbow stripes, sharp laser beams or symmetrical outlined cone.