Sure, here's an example of a simple Snake game implemented as a single HTML file using JavaScript. It can be played on a smartphone and utilizes pictograms. Remember to enclose the code in script tags.
This HTML code creates a game board with a snake that can be controlled using the arrow keys on a smartphone. The objective is to eat the green food and avoid hitting the walls or the snake's own body. The game ends when the snake collides with any of these obstacles, and the score is displayed in an alert message. After that, the game is reset and can be played again.