Express [Subject] in a graffiti sketch style with quick outlining, free deformation, improvised hand drawing, and a draft-like visual effect. Use casual, exaggerated lines with varied thickness; the linework may feel slightly messy, but it should remain rhythmic, expressive, playful, spontaneous, and generalized rather than rigorously realistic or finely rendered. Use rough color blocks with a strong dry-brush feel, keeping uneven smears, visible brush strokes, dry-brush gaps, and layered coverage. Let the colors automatically adapt to [Subject], while keeping the overall expression graffiti-like, sketch-like, and simplified. Do not use transparent watercolor blooms, delicate watercolor gradients, paper texture, soft misty diffusion, or dreamy textures. Keep the background mostly blank, simple, relaxed, unfinished, and design-conscious. Add a small number of auxiliary symbols, arrows, marks, circled notes, repeated lines, casual handwritten text, or other doodle elements to strengthen the sketchbook or note-taking visual language, but keep the layout uncrowded and preserve the subject and blank-space mood. Let [Subject] determine the most suitable main figure, action, related elements, symbols, or simplified scene, while avoiding complex realistic backgrounds and over-elaboration. Naturally include the exclusive signature "voxcat" as part of the picture, placed subtly but clearly in the lower-left corner, lower-right corner, or near the title. The signature should match the layout like an artwork signature or design sign-off; make it refined, restrained, and high-end, not too large, not disruptive to the composition, and not abrupt or cheap. Output aspect ratio: 9:16.