Geometrisches Monument-Poster im modernistischen Stil

You are a top-tier poster designer skilled in modernist visual storytelling, geometric composition, urban-imagery collage, and retro print illustration. Create an original vertical themed poster around the "theme" I enter at the end of the prompt. Important principle: Do not copy any existing work, specific designer, brand poster, logo, architectural arrangement, numeral styling, or original composition. What should be extracted and applied is a reusable design method: monumental large-scale composition, a geometric symbol dominating the image, architecturalized theme elements, limited color, retro halftone grain, and overlay of plane and space. The final image should convey a similar visual temperament and design maturity, but must be an original work reconceived for the new theme. Before generating the image, complete the following design reasoning internally; do not output the analysis process, only the final visual result: Step 1: Understand the theme Analyze the theme's emotion, cultural meaning, core values, representative objects, scenes, sense of time, and symbolic significance. Do not merely write the theme's name on the image; instead, transform the theme into a symbolic system that can be visualized. Step 2: Establish the core visual metaphor Choose the most powerful core concept from the theme and transform it into an enormous main visual motif. The main visual motif can be: a number, a letter, a Chinese-character structure, an arch, a ring, the sun, a wave, a mountain peak, a road, a container, a window, a plant silhouette, a mechanical structure, or an abstract geometric symbol newly created from the theme. This enormous symbol must occupy roughly 55% to 75% of the image area, becoming the skeleton of the composition rather than ordinary decoration. The main visual form should satisfy: bold outline, simple structure, strong recognizability; a monumental, architectural, and public-visual feel; can be partially obscured, cut, or interpenetrated; can be seen both as an abstract shape and understood as a symbol of the theme; avoid ordinary centered icons, simple symmetrical emblems, or common template compositions. Step 3: Transform the theme's elements into a "visual city" Automatically select 6 to 12 representative elements based on the theme. Do not depict them realistically; instead geometrize, architecturalize, silhouette, and modularize them. Transformation methods include: turning products into architectural blocks; turning human activities into simple silhouettes or public-sculpture-like forms; turning natural objects into mountains, ripples, arches, rings, or continuous curves; turning technological elements into towers, circuits, windows, light columns, and modules; turning cultural elements into roofs, gateways, patterns, stele forms, and structural nodes; turning abstract concepts into roads, staircases, bridges, rays of light, tracks, or upward forms. These elements should surround, embed into, pass through, or grow within the main visual motif, forming a fantasy city, stage, monument, or spiritual landscape composed of the theme. Step 4: Composition design Use a vertical poster composition, with an aspect ratio of about 2:3. Adopt an asymmetrical but stable composition: the main structure grows upward from the bottom of the image; the visual weight concentrates mainly in the lower-center; keep appropriate breathing space at the top; some shapes may extend beyond the canvas edges; front