The user wants a Gray-Scott reaction-diffusion simulation. This is a classic type of Turing pattern, which can generate very beautiful organic patterns. I need to create a complete single-page application containing all the code.

Let me first think about the core mechanics of Gray-Scott:

1. Gray-Scott Model Basics:
   - Two chemical substances: activator (U) and inhibitor (V)
   - Reaction: U + 2V → 3V and V → P (inert product)
   - Diffusion: U and V diffuse at different rates
   - Parameters: feed rate (f) and kill rate (k) control pattern formation

2. What I need to implement:
   - Two 2D arrays to store U and V concentrations
   - A fragment shader for GPU acceleration computing (WebGL)
   - Real-time rendering of patterns to canvas
   - Mouse interaction to add "seeds"

3. Technical choices:
   - Use HTML5 Canvas (better with WebGL for performance)
   - Use GLSL shaders for mass parallel computation
   - Require multiple ping-pong buffers to store states

4. Page structure:
   - Main canvas occupying the full screen
   - Simple control panel for adjusting parameters
   - Display of current simulation parameters

Let me start writing the complete HTML file. I'll create a self-contained solution that contains all necessary shaders, control logic, and UI elements.

I'll create a Gray-Scott reaction-diffusion simulation with mouse interaction for seeding patterns

Great! I've successfully created a complete Gray-Scott reaction-diffusion simulation. Let me verify that the file was created properly and that all the key components are in place.

Perfect! I've created a complete Gray-Scott reaction-diffusion simulation in a single `index.html` file. ## Features: **🎨 Real-time Turing Patterns**: The simulation uses WebGL2 shaders for GPU-accelerated computation, generating organic, flowing patterns that evolve continuously. **🖱️ Mouse Interaction**: Click and drag anywhere on the canvas to seed new pattern growth. The mouse acts as a "brush" that introduces the inhibitor chemical (V) to create new patterns. **⚙️ Interactive Controls**: - **Feed/Kill Rates**: Control the (f,k) parameters that determine pattern type - **Diffusion Rates**: Adjust how quickly chemicals spread - **Pattern Presets**: Pre-configured parameters for different pattern types (solitons, worms, mazes, spots, waves, etc.) - **Time Step**: Control simulation speed - **Reset**: Clear and reinitialize the simulation - **Randomize**: Generate random parameters for unexpected patterns **🔍 Zoom**: Use mouse wheel to zoom in/out and explore the patterns in detail. **📱 Mobile Support**: Touch interactions work seamlessly on mobile devices. The Gray-Scott model creates stunning organic patterns reminiscent of coral formations, animal coats, and chemical reactions. Different parameter combinations produce entirely different pattern morphologies - from stable spots to wandering worms to chaotic waves! Just open `index.html` in a modern web browser and start experimenting!