Create a 4×4 contact sheet containing exactly 16 equal-sized image cells. The ca...

Create a 4×4 contact sheet containing exactly 16 equal-sized image cells. The canvas is exactly 16:9 aspect ratio at 2K resolution. Each cell must have identical dimensions and each cell must maintain a 16:9 aspect ratio. Place the 12 provided thumbnail concepts into the first 12 cells only. The remaining four cells must be completely blank and unused. Do not resize, enlarge, reposition, or rearrange any of the 12 thumbnails to fill the empty cells. Use a seamless edge-to-edge grid with no visible gutters, no outer margins, no borders, no frames, no captions, no labels, and no text. Every populated cell must be the same size as every other populated cell. The final four cells contain a uniform dark gray empty placeholder tile with no imagery or text. Generate: 1. Scientific Illustration Scientific textbook-quality illustration. 2. Medical Visualization Anatomical educational visualization. 3. Technical Diagram Engineering schematic. 4. Architectural Visualization Building and interior visualization. 5. Educational Poster Teaching-focused visual explanation. 6. Mechanical Design Machine engineering concept. 7. Data Visualization Professional charts and analytical graphics. 8. Product Explainer Exploded product explanation. 9. Process Diagram Workflow visualization. 10. Historical Reconstruction Accurate historical scene. 11. Map Visualization Geographic information graphic. 12. Instruction Manual Step-by-step instructional visual.