As an AI text-based model, I can provide you with a basic template for a simple game implemented as a single HTML file with JavaScript. However, please note that implementing a full-fledged 3D open-world game within the constraints mentioned may not be feasible. Here's an example of a basic game structure using pictograms as requested:
This template sets up a canvas element where you can implement your game logic and rendering. In this example, a simple red square is displayed as the player's pictogram. You can update the `update` function to handle player input and update the game state accordingly. The `render` function clears the canvas and draws the current game scene, including the player pictogram.
Remember, this is just a minimal example to get you started. Implementing a full-fledged 3D open-world game would require much more complex code and resources.