Sure! Here's an example of a simple 3D game implemented as a single HTML file using JavaScript and enclosed in script tags:
In this example, you control a player represented by a red square in a 3D game world. You can play the game on a smartphone by touching the canvas to move the player around. The game loop continuously updates the game state and redraws the player's position on the canvas.
Note: This example uses 2D graphics to simulate a 3D game environment. Creating a true 3D game would require more advanced graphics techniques and libraries.