This example demonstrates a memory leak in d3-timer by creating a timer that runs indefinitely with a 150-millisecond delay. The page loads the d3-timer library from a CDN and instantiates a timer via `d3.timer()`, passing an empty callback that executes on each tick. The visualization shows how a timer persists without explicit disposal, highlighting potential performance issues in long-running applications. The code uses plain HTML and JavaScript with no rendering, making the leak’s behavior visible through browser developer tools rather than visual output.