Sure! Here's a simple game where four balls collide. The game is implemented as a single HTML file and contains JavaScript enclosed in script tags. The game starts processing as soon as it is loaded in a web browser.
To play the game, simply run the HTML file in a web browser on your smartphone. You will see four balls of different colors bouncing around the canvas. When any two balls collide, they will change their directions according to the physics of an elastic collision. Have fun playing the game!