Sure! Here's an example of a simple game implemented as a single HTML file, containing JavaScript and enclosed in script tags. This game displays a cube using 3D graphics and can be played on a smartphone.
To play the game, you can copy the above code and save it as an HTML file, then open the file using a web browser on your smartphone. The code will display a red cube on the screen. You can further enhance the game by adding interactivity and game logic, but this simple example demonstrates the basic rendering of the cube using HTML, JavaScript, and 3D graphics.